Question

two persons do the same amount of work the first person does it in 10 second and the second in 20 second find the ratio of power used by the first person to that by the second person

Answer 1

Let work done by both persons be W
therefore, Power used by both will be P1 & P2 respectively
therefore
Time taken by 1st person = 10 secs
Time taken by 2nd person = 20 secs
Formula -
$p = \frac{w}{t}$
therefore
Let
$p1 = \frac{w}{t1}$
$p2 = \frac{w}{t2}$
therefore taking ratios of both quantities we get
$\frac{p1}{p2} = \frac{ \frac{w}{t1} }{ \frac{w}{t2} }$
$\frac{p1}{p2} = \frac{t1}{t2}$
substitute the values we get final answer
$\frac{p1}{p2} = \frac{1}{2}$

Answer 2

Ans- 2:1
Work done=same
Power= work done/time taken
Power1/power2= work done1/time 1/work done2/time2=time2/time1=20/10=2/1