Linear equations

The number 27 is special because it is three times the sum of its digits 27 = 3 (2 + 7). Find some two digit numbers that are SEVEN times the sum of their digits (seven-up numbers)?

One night two candles were lit. Can you work out how long each candle was originally?

If you know that a fraction of X is the same as a different fraction of Y, can you work out X/Y?

Granny has taken up deep-sea fishing! Last week, she caught a fish so big that she had to cut it into three pieces in order to weigh it...

Consider a watch face which has identical hands and identical marks for the hours. It is opposite to a mirror. When is the time as read direct and in the mirror exactly the same between 6 and 7?

The product of Mary's age at her last birthday and her age in complete months is 1800. How old is Mary?