Question

1. Andrew ran a marathon in about 1.56 * 10^4s.

(a) Write Andrew’s time in standard notation.

(b) Evelyn ran a marathon in 4 h and 16 min.

Who ran the race in the shorter amount of time?
Show your work.

Answer 1

Answer-

Evelyn ran the race in the shorter amount of time.

Solution-

Time taken by Andrew to run the marathon is,

$=1.56\times 10^4\ s\\\\=1.56\times 10000\ s\\\\=15600\ s$

Converting this into standard notation, we have to write it in hours and minute form. As 1 hour contains 60 minutes or 3600 seconds, so

$=\dfrac{15600}{3600}=\dfrac{13}{3}=4\dfrac{1}{3}\ hours$

This is equivalent to 4 complete hours and one third of an hour. One-third of an hour is equal to  $\dfrac{60}{3}=20$ minutes, then

$4\dfrac{1}{3}\ hours=4\ hours\ 20\ minutes$

Andrew took 4 hours 20 minutes to complete the marathon, whereas Evelyn took 4 hours 16 minutes, so Evelyn took 4 minutes less than Andrew.

Therefore, Evelyn ran the race in the shorter amount of time.