In what ratio must oil at ₹60 per litre be mixed with oil at ₹90 per litre to get a mixture worth ₹70 per litre?

Explanation

1. 01

   Cheaper : dearer $= (d - m) : (m - c) = (90 - 70) : (70 - 60) = 20 : 10$.

2. 02

   In lowest terms, 2 : 1.