Rohit bought 12 registers for Rs 156, find the cost of 7 such registers.

Explanation

Let the cost of `7` registers be Rs.`x`
If he buys less number of registers, the cost will also be less.
∴ It is a direct variation.
`⇒ 12:7=156:x`
`⇒ x= (156×7)/12`
`⇒ x=91`
∴ The cost of `7` such registers will be Rs.`91`.