Increase and decrease in a given ratio

When increasing quantities in a given ratio, such as increasing R16 in the ratio 5:4, we use the method of dividing the given quantity by the smaller value in the ratio, in this case the 4, and then multiplying with the bigger value in the ratio, in this case the 5.

Thus, when R16 is increased in the ratio 5:4 we can do it as follows: R16 ÷ 4 x 5 = R20. Just ensure that the answer is bigger as the original one as it is an increase.

When decreasing quantities in a given ratio, you can follow the exact same method, however, in the case of decreasing quantities, you have to divide with the bigger value in the ratio and multiply with the smaller value in the ratio.