Ratio and Proportion — MATHS STD 7 — Question

4. 15 : 8

Solution:

As, $\text{2x}=3\text{y}$

$\Rightarrow\frac{\text{x}}{\text{y}}=\frac32$

And, $\text{4y}=\text{5z}$

$\Rightarrow\frac{\text{y}}{\text{z}}=\frac54$

Now, $\text{x}:\text{z}=\frac{\text{x}}{\text{z}}$

$=\frac{\text{xy}}{\text{yz}}$

$=\frac{\text{x}}{\text{y}}\times\frac{\text{y}}{\text{z}}$

$=\frac32\times\frac54$

$=\frac{15}{8}$

$=15:8$

Hence, the correct alternative is option (d).