SOLUTION: The length of a rectangle is increased by 30 percent and its width is increased by 20 percent. By what percent does the area increase? (A) 50 (B) 54 (C) 56 (D) 60 (E) 156

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Question 1187187: The length of a rectangle is increased by 30 percent and its width is increased by 20 percent. By what percent does the area increase?
(A) 50 (B) 54 (C) 56 (D) 60 (E) 156
Found 3 solutions by ikleyn, ankor@dixie-net.com, MathLover1:
Answer by ikleyn(52779) About Me  (Show Source):
You can put this solution on YOUR website!
.

By  (1+0.3)*(1+0.2) - 1 = 1.3*1.2-1 = 1.56 - 1 = 0.56 = 56%.    ANSWER

Solved.



Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The length of a rectangle is increased by 30 percent and its width is increased by 20 percent.
By what percent does the area increase?
(A) 50 (B) 54 (C) 56 (D) 60 (E) 156
:
let the original area = 1 * 1 = 1
the new area: 1.3 * 1.2 = 1.56
find the area increase .56/1 or 56%

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

A=LW
the length increase 30% =>L%2B0.30L=1.30L
the width increase 20%=>W%2B0.20W=1.20W
A1=%281.30L%29%281.20W%29
A1=1.56+LW++
difference
A1-A=1.56LW+-LW=%281.56+-1%29LW=+0.56LW+
=> increase of 56%