Rob has a bag with white, black and blue counters. There are twice as many blue counters than there are white. A qaurter of all the counters are black. If there are 5 white counters, how many counters are in the bag.

White:blue is 1:2. (There are twice as many blue counters)if there are 5 white counters there are 10 blue counterswhite + blue = 15in the bag there are the 15 white and blue counters PLUS the blacki.e. In the bag there are 15 + black (15 + black)/4 = black. (A quarter of the total counters were black)15 + black = 4 x black. (Rearrange the formula)15 = 4 x black - black15 = black(4 - 1)15 = black (3)15/3= black black = 55 + 10 + 5 = 20 counters in the bag (white = 5, blue = 10, black = 5)(this is a tricky question and would have multiple parts to it each giving the student more marks)