Problem Solving

cylindrical tank of radius R and height H must be redesigned to hold approximately twice as much liquid. Which of the following changes would be farthest from the new design requirements?

A.a 100% increase in R and a 50% decrease in H
B.a 30% decrease in R and a 300% increase in H
C.a 10% decrease in R and a 150% increase in H
D.a 40% increase in R and no change in H
E.a 50% increase in R and a 20% decrease in H

quicker and faster approach would be which one ?

Source : MGMAT QB

bhumika.k.shah wrote:cylindrical tank of radius R and height H must be redesigned to hold approximately twice as much liquid. Which of the following changes would be farthest from the new design requirements?

A.a 100% increase in R and a 50% decrease in H
B.a 30% decrease in R and a 300% increase in H
C.a 10% decrease in R and a 150% increase in H
D.a 40% increase in R and no change in H
E.a 50% increase in R and a 20% decrease in H

quicker and faster approach would be which one ?

Source : MGMAT QB

The new design requirements need the final volume to be 2 π R^2 H from π R^2 H, or it needs to be doubled (2 times).

QUICK CHECK is here

A. 2^2 × 0.5 = 2, (2 - 2 = 0)
B. 0.7^2 × 4 = 1.96, (2 - 1.96 = 0.04)
C. 0.9^2 × 2.5 = 2.025, (2.025 - 2 = 0.025)
D. 1.4^2 × 1 = 1.96, (2 - 1.96 = 0.04)
E. 1.5^2 × 0.8 = 1.8, (2 - 1.8 = 0.2), this is the GREATEST DEVIATION

[spoiler]E[/spoiler]