3. "a varies directly with b". If a = 4 when b = 21, find a when b-7.

Mathematics

2 answers:

Irina-Kira [14]3 years ago

8 0

Step-by-step explanation:

A(promotional sign)b

A=kb

4=21k

K=0. 1904

A=0. 2b

A=0. 2×7

A=1. 4

goldfiish [28.3K]3 years ago

7 0

Step-by-step explanation:

a varies directly with b

a ∞ b

a = Kb

K is the constant of proportionality

If a = 4 when b = 21

4 = 21×k

4 = 21k

k = 4/21

: - a = 4b/21

find a when b= 7.

a = 4(7)/21

a = 4/3

a = 1 1/3

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