S K Gupta and Anubhuti Gangal Solutions for Exercise 6: Mental Maths

Express the ratio $25 \mathrm{cm}$ to $1 \mathrm{m}$ in the simplest form.

Find the ratio of $18$ seconds to $1$ hour in the simplest form.

Divide $₹90$ in the ratio $3:7$.

Find $x$ in the proportion :

$6:x::3:7$

Determine whether the following are in proportion.

$2, 3, 4, 5$

Determine whether the following are in proportion.

$5, 6, 10, 12$

$16:24=20:30$

$5$ pens cost $₹12$. How much will $20$ pens cost?