Question

plz help me to find the answer​

Answer 1

Answer:

3. 12

Explanation:

3.

given,

m=1/6

u=30

we know that,

m=v/u

1/6 = v/ -30 since u is negative

v = -5

1/f= 1/v + 1/u

1/f = 1/5 - 1/30

1/f = 6-1/30

1/f =5/30

1/f = 1/6

f = 6 m

R=2f

  =2*6=12 m