Question

Sachin can cover a distance in 1hr 45 min by covering 2/3 of the distance at 4 kmph and the rest at 5 kmph. The total distance is?

Answer 1

Answer:

The total distance is 7.5 kms.

Step-by-step explanation:

Let d be the total distance.

Distance traveled at 4 km/h = $\frac{2}{3}d$.

Distance traveled at 5 km/h = (1 - $\frac{2}{3}$)d = $\frac{1}{3} d$.

Total time = 1 hr 45 min = (60 + 45) min = 105 min = $\frac{105}{60}$ hours = $\frac{7}{4}$ h

Time = $\frac{distance}{speed}$

= $\frac{\frac{2}{3}d }{4}$ + $\frac{\frac{1}{3}d }{5}$

= $\frac{1}{6}d$ + $\frac{1}{15}d$

= $\frac{7}{30}d$ h

Now we have:

$\frac{7}{4}$ = $\frac{7}{30}d$

Then:

d = $\frac{7 x 30}{7 x 4}$ = $\frac{210}{28}$ = 7.5 km

Hence, the total distance is 7.5 kms.