Question

If 30% of a number is 1200, then what is the ratio of 40% of the number thus obtained to 40% of 1200?

• A. 10 : 3
• B. 3 : 10
• C. 30 : 15
• D. 20 : 3

Answer 1

The correct option is A 10 : 3

Given, 30% of a number = 1200
Let the number be 'n'.
$\Rightarrow 30\text{\% of n}=1200$
$\Rightarrow \frac{30}{100}\times n=1200$
$\Rightarrow n=\frac{1200\times 100}{30}$
$\Rightarrow n=4000$
Hence the number obtained is 4000.
Now,
$40\%\text{of}4000=\frac{40}{100}\times 4000=1600$
Also,
$40\%\text{of}1200=\frac{40}{100}\times 1200=480$
Hence, the required ratio is
$=1600:480$
$=\frac{1600}{480}$
$=\frac{10}{3}$
$=10:3$