Remember, the volume formula of a sphere is

.
Set that equation equal to whatever volume they give you and solve for r.

=

Now solve for r! I know you can do this. If you need help, just comment.
Answer:
8.9%
Step-by-step explanation:
Answer:
£0.50
Step-by-step explanation:
t = one cup of tea
c = one piece of cake
t + c = £1.10
2t + c = £1.70
the cost increases by £0.60 (£1.70 - £1.10) when you order one more cup of tea which means that one cup of tea costs £0.60
substitute £0.60 into t + c = £1.10
£0.60 + c = £1.10
rearrange to get c = £1.10 - £0.60 = £0.50
so one piece of cake costs £0.50
Step 1
Let n represent car and m represent motorcycles.
n + m = 50 ...................1
car has four wheels and motorcycle has two wheels
4n + 2m = 164 .............................. 2
Step 2
Solve equation 1 and 2 simultaneously.
from (1), make n subject of relation and substitute in equation 2.
n = 50 - m
Step 3
Substitute n in equation 2
4(50 - m) + 2m = 164
200 - 4m + 2m = 164
collect like terms
200 - 164 = 4m - 2m
36 = 2m
m = 36/2
m = 18
next find n
n = 50 - m
n = 50 - 18
n = 32
There are 32 cars and 18 motorcycles.
78 rounded to the nearest tenth is 80