Well, for number three. You know that the length of the RECTANGULAR garden is 6.8 meters. Since it is a rectangle the garden will have 4 sides:two lengths and 2 widths. an easy way to find the width is to multiply the single length by 2, so 6.8 meters becomes 13.6. Then, you subtract that from the total perimeter, this leaves you with 7 meters. Those 7 meters are the sum of both width sides added together, so all you have to do is divide 7 by 2 to get 3.5 meters as your width. Before I go on do you understand how I got that number?
-4m-8=-8-4m
+4 +4
__________
-8=-8
or
1=1
If there is 10% of $18 = 18 x 0.9 (1 - 0.1) = $16.20
Therefore the pie costs $16.20
He is saving 18 - 16.20 = $1.80
