Explain how to find the area of a figure using square tiles

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

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

Over the last 4 seconds, a snail has traveled 4/9 of an inch. if the snail traveled the same distance each second, how far did it travel each second?