48
+14
-------
62
If you need more work:
Ones place: 8+4=12
Tens place: 40+10=50
Add up: 50+12=62
B
the volume (V) of a sphere =
πr³
We require to know the radius r to calculate the volume
using surface area of a sphere = 4πr² = 615.752
divide both sides by 4π
r² =
= 49.0248...
take the square root of both sides
r =
≈ 7, hence
V=
× π × 7³ = 1436.76 m³ → B
In the first one it would be (21-8)-6=7.
and in the second one it would be 21-(8-6)=19