Question: Oliver owns a laundry shop, and he charges $2 per kilo of laundry. Two days ago, his shop washed a total of 5 kilos of laundries. Yesterday, it washed five kilos of laundries more than the previous day. Today, it washed twice the number of kilos than yesterday.  How much did he earn for three days? Think carefully first, then make a decision:
Yesterday, his shop washed 5 + 5 = 10 kilos of laundry. Today, it washed 2 x 10 = 20 kilos of laundry. Thus, Oliver's shop washed a total of 5 + 10 + 20 = 35 kilos of laundries for three days. Therefore, his shop earned 35 x $2 = $70 for three days. So the answer is 70.