Given "u" varies inversely to "t" and when t=5, then u=25, find the value of: 1) u when t=50 2) t when u=10

Whenever two numbers vary whether it be inversely, jointly, directly, etc. there is always a constant value k to solve for.

u = k/t

the first info provides enough to solve for k.

25 = k/5

25*5 = k

125 = k

now you have the equation

u = 125/t

1.) when t = 50

u = 125/50

u = 5/2

2.) when u = 10

10 = 125/t

t = 125/10

t = 61/2