Question

In the evening, Chef Locus Lime has $5:00\text{PM}\text{to}6:30\text{PM}$ to swim laps around the pool. If he takes $15$ minutes to complete one lap, he can swim laps in the designated time.
If he increases his pool time from $6:30\text{PM}$ to $7:15\text{PM}$, he can complete more laps.

Answer 1

Chef's pool time initially is from $5:00\text{PM}\text{to}6:30\text{PM}$

So, total time for Chef to swim laps $=1\text{hour}\text{and}30\text{min}$$=1\times 60+30=60+30=90$ minutes

Time taken by Chef to complete $1$ lap $=15$ minutes

Therefore, number of laps that Chef can complete in the given time $=\frac{\text{total time}}{\text{time taken for one lap}}=\frac{90}{15}=6$

Afterwards, Chef increases his time from $6:30$ pm to $7:15$ pm.

So, extra time for Chef $=7:15-6:30$
To calculate the extra time, we have to subtract the timings.
For this, we will convert the hours to minutes and do the subtraction.

$7:15=(7\times 60)+15=420+15=435$ minutes

$6:30=(6\times 60)+30=360+30=390$ minutes

Therefore, extra time in minutes $=435-390=45$

Chef can swim one lap in $15$ minutes
So, the extra laps he can swim after increasing time
$=\frac{\text{total time}}{\text{time taken for one lap}}=\frac{45}{15}=3$

So Chef can swim 6 laps from $5:00$ pm to $6:30$ pm.
On increasing time from $6:30$ pm to $7:15$ pm, he can swim $3$ laps extra.