Level 3
Adam and Bryan builds a toy car in 4 hours.
Bryan and Chris builds a toy car in 6 hours.
Chris and Adam builds a toy car in 3 hours.
How long does it take for Adam, Bryan and Chris to build a toy car together?
Level 2
A box contains some red, yellow and blue sweets. The ratio of the number of red sweets to the number of yellow sweets is 2 : 3. The ratio of the number of yellow sweets to the number of blue sweets is also 2 : 3. What is the ratio of the number of red sweets to the number of blue sweets in the box?
Level 3
Some children board a school bus.
At Bus Stop A, 25 of them alight
and 6 children board.
At Bus Stop B, 13 of the children alight
and 4 board.
If there are 20 children on the bus now,
how many children are on the bus at first?
