Question

An electric car regains some of its power from braking such that every 10 miles driven generates enough power to travel 1 more mile. If the car can travel 1000 miles on a full charge using regenerative braking, how far can it travel without it? (Estimate the answer to the nearest one.)

• A. 900 miles
• B. 910 miles
• C. 909 miles
• D. 908 miles

Answer 1

The correct option is C 909 miles

For every 10 miles run of battery power, 1 mile is run of power generated from braking.

This cycle repeats multiple times to cover 1,000 miles in total.

Hence, if "x" is the number of such cycles, we get:

$(10+1)\times x=1000$
$⟹11x=1000$
$⟹x=\frac{1000}{11}$

As, the cycle is repeated "x" times, the number of miles run without regenerative braking will be:

$10\times x=10\times \frac{1000}{11}=\frac{10,000}{11}=909.09$

Rounding this to the nearest one, we get:

$909.09miles\approx 909miles$