Question

If a: b = 5: 7 and c: d = 2a: 5b then ac : bd is?
(a) 20: 38
(b) 10: 49
(c) 10: 21
(d) 50: 151

Answer 1

a:b::c:d=non of these because all options r wrong. !-!
be brainly

Answer 2

Answer:

10 : 49

Step-by-step explanation:

Given :a: b = 5: 7 and c: d = 2a: 5b

To Find : ac : bd

Solution :

$\frac{a}{b} \times \frac{c}{d}=\frac{5}{7} \times \frac{2a}{5b}$

$\frac{a}{b} \times \frac{c}{d}=\frac{10}{35} \times \frac{a}{b}$

$\frac{a}{b} \times \frac{c}{d}=\frac{10}{35} \times \frac{5}{7}$

$\frac{a}{b} \times \frac{c}{d}=\frac{50}{245}$

$\frac{a}{b} \times \frac{c}{d}=\frac{10}{49}$

So,  ac : bd =10 : 49

Hence Option B is true