Question

If $7kg$ onions cost $140$ rupees, how much must we pay for $12kg$ onions?

Answer 1

Given: $7kg$ onions cost $140$ rupees.
Let us suppose the cost of $12kg$ onions is $x$ rupees.
The number of onions and their cost vary in direct proportion.
$\therefore \frac{7}{140}=\frac{12}{x}$
$\Rightarrow x=12\times \frac{140}{7}$
$=12\times 20$
$=240$ rupees
Hence, the cost of $12kg$ onions is $240$ rupees.