If a, b, and c are integers such that the product of a, b and c is 20

Question

If a, b, and c are integers such that the product of a, b and c is 20 and  c > 4 > a \geq b . Which of the following could be the value of b + a?

A. 11
B. 10
C. 8
D. 2
E. –10

falewman · Answer

Of the few possible choices for 'c', I choose c=20. If c=20, then a=b=1. Hence b+a = 1+1 = 2

My answer is D

Salvetor · Answer

Answer is D. 
Assume c is 20
A and b is one. So it fits the bill

broall · Answer

$abc=20 \implies ab > 0$. 
Hence, $c>4 \implies ab>5$ $\implies (a+b)^2 \geq 4ab>20 > 16 = 4^2$ $\implies -4 \leq a+b \leq 4$

It's clear that the remain choice is D.

sarvaanjan · Answer

Given,
abc=20
20 can be written as,
20=1x20
 =2x10
 =4x5
 =5x4
 =10x2
 =20x1
abc=(c)x(ab)
Since c>4,c can be 5,10,20.This means ab can be 4,2,1
Case1:ab=4
(a,b)=((1,4),(2,2),(4,1)).This means a+b can be 5,4
Case2:ab=2
(a,b)=((2,1),(1,2)).This means a+b can be 3
Case3:ab=1
(a,b)=((1,1)).This means a+b can be 2
Also,c>b,a
So,a+b can be 2,3
The answer is D

JeffTargetTestPrep · Answer

We are given that a, b, and c are integers such that the product of a, b, and c is 20 and c > 4 > a ≥ b.

We see that c must be greater than 4, and that a and b must be less than 4 but could also equal each other.

Let’s list out some possible options for the values of a, b, and c, noting that their product must be 20.

a = 1, b = 1, c = 20

We see that in this case a + b = 1 + 1 = 2, which is answer D.

Answer: D

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

If a, b, and c are integers such that the product of a, b and c is 20

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

If a, b, and c are integers such that the product of a, b and c is 20

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards