Answer:
90.60 pounds
Explanation:
So with this question, we have both a set rate and a variable rate.
To work out the answer, we will find the cost of calls made. To do this, we need to multiply the amount of minutes of calls by the rate given.
In this case, it costs 18p per minute, and 420 minutes of calls have been made. So we will multiply 18p by 420 minutes:
18 x 420 = 7560p
When we convert this to pounds, it becomes 75.60 pounds.
We add this amount to the set rate, which is 15 pounds:
75.60 + 15 = 90.60 pounds
(I hope I did the conversion from pence to pounds right, my currency is the dollar, so I wasn't completely sure.)
Hope this helps,
Cate