Question 1192168
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When full, a car's petrol tank holds k litres. After using 15 e, the remaining petrol is enough for the car to travel 344 km.
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k, the tank's capacity in liters.
k-15e, amount in the tank after removing 15e.

{{{344/(k-15e)}}}, fuel efficiency in kilometers per liter.



Given also, fuel efficiency 8  kilometers per liter
then
{{{8=344/(k-15e)}}}
and you can solve for k.