Question

First 100 units = 24p per unit Remaining units = 16p per unit Mrs. Watt checks her electricity bill. Here are her meter readings. New reading: 7143 units Old reading 6997 units (A) User subtraction to calculate the number of units used. (B) Calculate the cost of the number of units used

Answer 1

Answer: a) 146 units used b) the cost of the number of units used is 3136 p.

Explanation:

Since we have given that

First 100 units = 24 p per unit

Remaining units = 16 p per unit

New reading = 7143 units

Old reading = 6997 units

Difference between the readings would be

`7143-6997\\\\=146`

So, there are 146 units used.

(B) Calculate the cost of the number of units used

There are 146 units

For the first 100 units = 24 p per unit

For the remaining i.e. 146-1400 = 46 units , cost = 16 p per unit

Total cost of the number of units used is given by

`24* 100+46* 16\\\\=2400+736\\\\=3136\ p`

Hence, a) 146 units used b) the cost of the number of units used is 3136 p.