Check the picture below.
so notice, their perimeter is the same, because the perimeter is just one rod anyway, and all rods are the same length, thus
18 x 20 = 360
360 / 20 = 18
So 18 is the answer
1. Natasha invests £250 in a building society account. At the end of the year her account is
credited with 2% interest. How much interest had her £250 earned in the year?
Solution: Interest = 2% of £250
= 2/100 x £250
answer = £5
2. Alan invests £140 in an account that pays r% interest. After the first year he receives £4.20 interest. What is the value of r, the rate of interest?
r/100 x £140 = £4.20
r = 100 x 4.20 / 140
= 420/140
= 3%
So the interest rate is 3%
Answer
43.96 in.2
Solution
31.4+12.56
= 43.96
