Solve the problem.
-The time T necessary to make an enlargement of a photo negative varies directly as the area A of the enlargement. If 45 seconds are required to make a 3-by-5 enlargement, find the time required for a 4-by-7
Enlargement.
A) 140 sec
B) 56 sec
C) 84 sec
D) 112 sec

Question

Quizplus · Accepted Answer

The area of the 3-by-5 enlargement is 15 square units, and it takes 45 seconds. The area of the 4-by-7 enlargement is 28 square units. Since time varies directly with area, we set up the proportion: 45/15 = T/28. Solving for T gives T = 84 seconds.

Solve the Problem. -The Time T Necessary to Make an Enlargement of a Enlargement