Question

In a 100 meter race, Sam runs at a speed of 1.66 m/s. If Sam gives a start of 4m to Jack and still beats him by 12 seconds, what is the speed of Jack in m/s

Answer 1

Sam's speed = 1.66m/s Distance =100m Time taken by Sam= 100÷1.66= 60.24 sec = 60 seconds Jack's speed= Distance/time = (100-4)÷ (60+12) =96÷60+12 =96÷72=1.33m/s

Answer 2

Answer:

The speed covered by Jack in that 100 m race is 1.328 m/s.

Solution:

For Sam,  

Total Distance = 100 m.

Speed at which Sam runs = 1.66 m/s.

We know that,

$\begin{array} { c } { \therefore \text { Time } = \frac { \text { Distance } } { \text {speed} } } \\\\ { = \frac { 100 m } { \frac { 1.66 m } { s } } = \frac { 10000 } { 166 } \mathrm { sec } } \\\\ { \text { Time } = 60.24 \text { seconds. } } \end{array}$

For Jack,  

Time = 12 seconds more than Sam

= 60.24 + 12 seconds. = 72.24 seconds.

Distance = (100 - 4)m = 96m

$\begin{array} { c } { \therefore \text { Speed } = \frac { \text { Distance } } { \text {Time} } } \\\\ { \text { Speed } = \frac { 96 m } { 72.24 s } = 1.328 \mathrm { m } / \mathrm { s } } \end{array}$

Thus, the speed covered by Jack in that 100 m race is 1.328 m/s.