Question

Given that a/b=3/5 and b/c=4/5
Find a:b:c giving your answer in its simplest form

Answer 1

Answer:

12 : 20 : 25

Step-by-step explanation:

Express the ratios in terms of a

$\frac{a}{b}$ = $\frac{3}{5}$ ( cross- multiply )

3b = 5a ( divide both sides by 3 )

b = $\frac{5}{3}$ a

$\frac{b}{c}$ = $\frac{4}{5}$ ( cross- multiply )

4c = 5b ( divide both sides by 4 )

c = $\frac{5}{4}$ b = $\frac{5}{4}$ × $\frac{5}{3}$ a = $\frac{25}{12}$ a

Then

a : b : c

= a : $\frac{5}{3}$ a : $\frac{25}{12}$ a ( multiply each part by 12 to clear the fractions )

= 12a : 20a : 25a ( divide each part by a )

= 12 : 20 : 25