Question

The cost of a botttle of mayonnaise is $0.\overline{7}$ times the cost of a bottle of vinegar. If the cost of a bottle of vinegar is ₹90, then find the cost of a bottle of mayonnaise.

• A. ₹70
• B. ₹80
• C. ₹90
• D. ₹120

Answer 1

The correct option is A ₹70

Let $x$ = $0.\overline{7}$ , then $10x$ = $7.\overline{7}$
$10x$ - $x$ = $7.\overline{7}-0.\overline{7}$
$\Rightarrow 9x=7$
$\Rightarrow x=\frac{7}{9}$

Given, the cost of vinegar = ₹90

Hence, the cost of mayonnaise
= $\frac{7}{9}\times 90$
= ₹70