Question: The sum of prime numbers that are greater than 60 but less than 70 is

(A) 67
(B) 128
(C) 191
(D) 197
(E) 260

Correct Answer: B
Solution and Explanation:

Approach Solution 1:
Given :

The prime numbers that are greater than 60 , but less than 70

Since prime numbers are natural numbers that are divisible by only 1 and the number itself.
So the prime numbers that are greater than 60, but less than 70 are 61 and 67

Since the prime numbers that are greater than 60 , but less than 70 are 61 and 67
Hence the required sum of prime numbers that are greater than 60 , but less than 70
= 61 + 67
= 128

Approach Solution 2:
Prime number: Nos which has exactly two factors(1 and number of itself)
Prime Nos greater than 60 and less than 70 are 61 and 67
Hence, sum of prime Nos= 61+67= 128

Approach Solution 3:
A prime number is a number that has only two factors: 1 and itself. Therefore, a prime number is divisible by two numbers only.

Let's list the numbers from 61 to 69.
61, 62, 63, 64, 65, 66, 67, 68, 69

Immediately even numbers can be eliminated because they are divisible by 2 and thus are not prime.

We are now left with: 61, 63, 65, 67, 69
We can next eliminate 65 because 65 is a multiple of 5.
We are now left with 61, 63, 67, 69.

To eliminate any remaining values, we would look at those that are multiples of 3. If you don’t know an easy way to do this, just start with a number that is an obvious multiple of 3, such as 60, and then keep adding 3.

We see that 60, 63, 66, 69 are all multiples of 3 and therefore are not prime.

Thus, we can eliminate 63 and 69 from the list because they are not prime.

Finally, we are left with 61 and 67, and we must determine whether they are divisible by 7. They are not, and therefore they must be both prime.
Thus, the sum of 61 and 67 is 128.

“The sum of prime numbers that are greater than 60 but less”- is a topic of the GMAT Quantitative reasoning section of GMAT. This question has been taken from the book "The Official Guide for GMAT Review".To solve GMAT Problem Solving questions a student must have knowledge about a good amount of qualitative skills. GMAT Quant practice papers improve the mathematical knowledge of the candidates as it represents multiple sorts of quantitative problems.

Suggested GMAT Problem Solving Samples

• If x and y Are Positive Odd Integers, And Both Numbers Have An Odd Number Of Positive Divisors GMAT Problem Solving
• Copper Pipe Costs x Cents Per Foot in 8-Foot Lengths GMAT Problem Solving
• Find The Smallest Positive 4-Digit Number Which, When Increased by 8, is Divisible by 12, 18, 30, and 45 GMAT Problem Solving
• How Much Pure Alcohol Should Be Added To 400 ml of a 15% Solution To Make The Strength Of The Solution 32%? GMAT Problem Solving
• 16 Ounces of Birdseed Mix Contains 10% Sesame Seed by Weight GMAT Problem Solving
• The Diameter of Circle S is Equal in Length to a Side of a Certain Square GMAT Problem Solving
• In a college of 300 students, every student reads 5 newspapers and every newspaper is read by 60 students. GMAT Problem Solving
• If The Sum of 9 Consecutive Integers is 90 GMAT Problem Solving
• If a Carton Containing a Dozen Mirrors is Dropped GMAT Problem Solving
• Two Solutions Having Milk and Water in the Ratios 3 : 5 and 4 : 7 are GMAT Problem Solving
• A Mixture of 40 Liters of Milk and Water Contains 10% Water GMAT Problem Solving
• The Number 2 - 0.5 is How Many Times the Number 1 - 0.5? GMAT Problem Solving
• If n = 3, What is The Value of 2^2n+1? GMAT Problem Solving
• Which of the Following is Equal to 5^17×4^9? GMAT Problem Solving
• In a Group of 6 Boys and 4 Girls, Four Children Are to be Selected GMAT Problem Solving
• Which of the Following Fractions has a Decimal Equivalent that is a Terminating Decimal? GMAT Problem Solving
• The Price of Onions Increases by 25%, by what Percent should a Housewife Reduces the Consumption so that Expenditure on Onions can be Same as Before? GMAT Problem Solving
• A and B are Two Alloys of Gold and Copper Prepared By Mixing Metals in GMAT Problem Solving
• For integers x and y, 2^x+2^y=2^30. What is the value of x+y? GMAT Problem Solving
• United Telephone charges a base rate of $10.00 for service, plus an additional charge of $0.25 per minute. Atlantic Call charges a base rate of $12.00 for service GMAT Problem Solving
• Lamp A Flashes Every 6 seconds, Lamp B Flashes Every 8 seconds, Lamp C Flashes Every 10 seconds GMAT Problem Solving
• At a Sandwich Shop, There are 2 Breads, 3 Kinds of Meat, 4 Types of Cheeses GMAT Problem Solving
• A Survey was Conducted Among 1000 People to Know About their Eating Habits GMAT Problem Solving
• Jake Rides His Bike for the First 2/3 of the Distance From Home to School GMAT Problem Solving
• Two Trains Running in Opposite Directions Cross a Man Standing on the Platform GMAT Problem Solving
• The Owner of A Local Jewellery Store Hired 3 Watchmen to Guard his Diamonds GMAT Problem Solving
• What is the smallest integer n for which 25^n>5^12 GMAT Problem Solving
• Ten Coins are Tossed Simultaneously. In how many of the Outcomes GMAT Problem Solving
• A Pool can be Filled in 4 Hours and Drained in 5 Hours GMAT Problem Solving
• If x^2 − 2 < 0, which of the following specifies all the possible GMAT Problem Solving
• A Train Approaches A Tunnel AB. Inside The Tunnel Is A Cat Located GMAT Problem Solving
• A Dairyman Pays Rs. 6.40 Per Liter Of Milk GMAT Problem Solving
• John is 20 years older than Brian. 12 years ago, John was twice as old GMAT Problem Solving
• A Train Overtakes Two Persons Who Are Walking In The Same Direction GMAT Problem Solving
• If 1/x − 1/x+1= 1/x+4, Then x could be GMAT Problem Solving
• If x = - |x|, Then Which One of the Following Statements GMAT Problem Solving
• A Bag Contains 4 Red and 3 Black Balls. A Second Bag Contains 2 Red GMAT Problem Solving
• A Mixture of 40 Litres of Milk and Water, Contains 20% of Water GMAT Problem Solving
• A Candidate is Required to Answer 6 Out of 10 Questions Divided into 2 Groups GMAT Problem Solving
• Company XYZ had $498.2 Million in Profits for the Year GMAT Problem Solving
• If -2 < a < 11 and 3 < b < 12, Then Which of the Following is NOT Always True GMAT Problem Solving
• Karan and Arjun run a 100-metre Race, Where Karan Beats Arjun by 10 metres GMAT Problem Solving
• Set T consists of all points (x, y) such that \(x^2+y^2=1\) GMAT Problem Solving
• How Many Natural Numbers Not Exceeding 4321 can be Formed GMAT Problem Solving
• The Figure below Shows an Equilateral Triangle ABC Tangent GMAT Problem Solving
• In an Isosceles Triangle PQR, If ∠Q = 80 Degrees, Then What is The GMAT Problem Solving
• If x=10^{10},\frac{x^2+2x+7}{3x^2-10x+200} is closest to GMAT Problem Solving
• If set S Consists of all Different Solutions of Equation |x – 4| = x, What is the Range of Set S GMAT Problem Solving
• Two Members of a Club are to be Selected to Represent the Club GMAT Problem Solving
• The Square Root of 24336 is Exactly GMAT Problem Solving