Expert: Paul Klarreich - 1/14/2011

Question
The time T necessary to make an enlargement of a photo negative varies directly as the area A of the enlargement. If 24 seconds are required to make a 3-by-4 enlargement, find the time required for a 5-by-6 enlargement.

Answer
Questioner: amiee
Country: United States
Category: Advanced Math
Private: Yes   <<<  Corrected.  No private q's please.
Subject: precalculus
Question: The time T necessary to make an enlargement of a photo negative varies directly as the area A of the enlargement. If 24 seconds are required to make a 3-by-4 enlargement, find the time required for a 5-by-6 enlargement.
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Do some translation:

The time T necessary to make an enlargement of a photo negative varies directly as the area A of the enlargement.

cut words:

The time T     varies directly as     the area A.

interpret:

The time T  equals a constant times the area A.

symbolize:

T = kA

Now substitute T = 24, A = 12 to get k.

Then

find the time required for a 5-by-6 enlargement

means:

find T when A = 30.

You can finish.