Price of a lap-top is reduced by 25% to 637.50. What is the original price?

Since you took away 25% from the 100% value, we know 637.50 is 75% of the full value. So divide it by three to get the 25% value of 212.50, then multiply by 4 to get the full value of 850. So the original price was $850.

The original price is 478.13 (if you round it) because 637.50 times. 25 (its. 25 because you need to turn it into a decimal) equals 159.375 then you subtract 637.50 by 159.375 and you get 478.125 then you round and get 478.13