Linear equations

problem
Fair shares?

Age

14 to 16

Challenge level

A mother wants to share a sum of money by giving each of her children in turn a lump sum plus a fraction of the remainder. How can she do this in order to share the money out equally?
problem
Seven up

Age

11 to 14

Challenge level

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)?
problem
Fibs

Age

11 to 14

Challenge level

The well known Fibonacci sequence is 1 ,1, 2, 3, 5, 8, 13, 21.... How many Fibonacci sequences can you find containing the number 196 as one of the terms?
problem
Tweedle Dum and Tweedle Dee

Age

11 to 14

Challenge level

Two brothers were left some money, amounting to an exact number of pounds, to divide between them. DEE undertook the division. "But your heap is larger than mine!" cried DUM...
problem
A problem of time

Age

14 to 16

Challenge level

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?
problem
Burning down

Age

14 to 16

Challenge level

One night two candles were lit. Can you work out how long each candle was originally?
article
A method of defining coefficients in the equations of chemical reactions

A simple method of defining the coefficients in the equations of chemical reactions with the help of a system of linear algebraic equations.