Answer:
x + Y = 39 or x = 39-y
20x + 50y = 1.40
20 (39 - y) + 50y = 11.40
7.80 - 20y + 50y = 11.40
30y = 11.40 - 7.80
30y = 3.60
y = 3.60/30
y = 12 50p coins were collected.
x = 39 - 12 = 27 20p coins were collected.
Proof:
20*27 + 50*12 = 11.40
5.40 + 6 = 11.40
11.40 = 11.40
I hope it helps.
Multiplication would be the inverse operation of division. so it would be, 3 x 34 = 102
In this problem, we are asked to give an expression that can be used to mentally multiply 6 and 198. In order not to go through the rigorous multiplication, we can estimate 198 to 200, that is 6 *200 equal to 1200. Since there is a 2*6 excess or 12 then we subtract: 1200 -12 equal to 1188.