Question: John is 20 years older than Brian. 12 years ago, John was twice as old as Brian. How old is Brian?

1. 20
2. 24
3. 28
4. 32
5. 36

Correct Answer: (D)
Solutions and Explanation
Approach Solution - 1 :

It is given that John is 20 years senior to Brian.
We can write that as J=B+20, let this be equation (1)

John was twice as old as Brian 12 years ago.
This can be written as J-12 = 2*(B-12), let this be equation (2)

The equations can be solved by substituting the value of J

Therefore we can get ,
(B+20-12 = 2*(B-12)
=> B+8 = 2B-24
=> B = 32

Approach Solution - 2 :

Let the age of Brian from twelve years ago be X.
John = 2X

Then,

Brian = X+12
John = 2X+12 (or) X+12+20
Let X+12+20 = 2X+12,
Therefore, X = 20

Put the following back into the equation:
Now, Brian age will be 20+12 = 32

“John is 20 years older than Brian. 12 years ago, John was twice as old” - is a topic of the GMAT Quantitative reasoning section of GMAT. To solve GMAT Problem Solving questions a student must have knowledge about a good number of qualitative skills. GMAT Quant section consists of 31 questions in total. The GMAT quant topics in the problem-solving part require calculative mathematical problems that should be solved with proper mathematical knowledge.

Suggested GMAT Problem Solving Samples

• The Figure Shown Above Consists of a Shaded 9-Sided Polygon GMAT Problem Solving
• A and B Can Do a Piece Of Work in 10 Days, While B And C Can Do The Same Work in 15 Days And C and A in 25 Days GMAT Problem Solving
• How Many 3-digit Positive Integers With Distinct Digits Are There, Which are not Multiples of 10? GMAT Problem Solving
• If x^3 < 16x Which Of The Following Includes at Least Some of the Possible Solutions for x GMAT Problem Solving
• What Is The Smallest Five Digit Number That Is Divisible by 16, 24, 36 and 54? GMAT Problem Solving
• A list of measurements in increasing order is 4, 5, 6, 8, 10 and x GMAT Problem Solving
• If the population of a town is p in the beginning of any year then it becomes 3+2p GMAT Problem Solving
• The Revenues and Costs, in Thousands of Dollars, for a Small Company in the Year 2007 GMAT Problem Solving
• Which of the following is a perfect square? GMAT Problem Solving
• In the xy-plane, the Vertices of a Triangle have Coordinates (0,0),(3,3), and (7,0) GMAT Problem Solving
• Rahul Can Finish a Job in 30 Days GMAT Problem Solving
• How Many Two-Digit Numbers Are Divisible By Both 5 and 6? GMAT Problem Solving
• If O is the Center Of The Circle, What is The Perimeter Of The Sector GMAT Problem Solving
• The Sum of 5 Numbers in the Geometric Progression is 24 GMAT Problem Solving
• Two Students Appeared At An Examination. One of Them Secured 9 Marks GMAT Problem Solving
• x' is a Positive Integer and x^3 is Divisible by 27 GMAT Problem Solving
• Which of the Following Equation is NOT Equivalent to 25x^2 = y^2 - 4? GMAT Problem Solving
• The Variable x is Inversely Proportional to the Square of the Variable GMAT Problem Solving
• Which of the Following Fractions is Closest to 1/2? GMAT Problem Solving
• In a Certain Game, You Pick a Card From a Standard Deck GMAT Problem Solving
• The Average of 20 Numbers is Zero. Of them, at the Most, How Many May GMAT Problem Solving
• A Can Contains a Mixture of Two Liquids A and B in the Ratio 7:5 GMAT Problem Solving
• 16 Ounces of Fresh Orange Juice Contains 216 Calories GMAT Problem Solving
• An Urn Contains 6 Red, 4 Blue, 2 Green and 3 Yellow marbles GMAT Problem Solving
• The Price of Raw Materials Has Gone up by 15% GMAT Problem Solving
• In a Class of 100 Students 70 Passed in Physics, 62 Passed in Mathematics GMAT Problem Solving
• 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 45GMAT 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 90GMAT Problem Solving
• If a Carton Containing a Dozen Mirrors is Dropped 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
• Is Square Root = Always Positive? ​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 Solvingl
• Two Trains Running in Opposite Directions Cross a Man Standing on the Platform GMAT Problem Solving
• Initial Population of a Town was 8000 People GMAT Problem Solving
• The Volume of a Sphere with Radius r is (4/3)*pi*r^3. A Solid Sphere GMAT Problem Solving
• Which of the Following is Equal to 5^17×4^9? GMAT Problem Solving
• In a Shooting Competition, Probability of A Hitting Target is 2/5, by B is 2/3 and C is 3/5 GMAT Problem Solving
• The Sides of a Quadrilateral Taken in Order are 16,16,14 and 10GMAT Problem Solving
• If 80 Lamps Can Be Lighted, 5 Hours Per Day For 10 Days GMAT Problem Solving
• If <d> denotes the area of a circle with diameter d, then which of the following is equal to <4>*<6> GMAT Problem Solving