A supply of coal was made for two boiler houses. One boiler house consumes 1/8 of the coal during a month

A supply of coal was made for two boiler houses. One boiler house consumes 1/8 of the coal during a month, and the second – 2/7 of the coal supply. What part of coal will both boiler houses use up in 3 months?

1. We find out what part of the coal both boiler houses will consume in one month, if we are given that the first boiler house needs 1/8 of the coal reserves for a month, and the second boiler house needs 2/7 of the supply.
1/8 + 2/7 = 7/56 + 16/56 = 23/56 part of the stock.
2. And now we will find out how much of the coal will be consumed by both boiler houses in three months.
23/56 * 3 = (23 * 3) / 56 = 69/56 = 1 13/56 stocks.
Answer: Two boiler houses for three months require coal 1 13/56 of the available reserves.