Leo writes the incorrect equation below. How can change the equation to make it true

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.

If it 8 inch candle burns at 7/10 inch per hour and a 6 inch candle burns at 1/5 inch per hour after how many hours would both candles be the same height