Answer:
the number of child plates and adults plates were served is 125 and 155 respectively
Step-by-step explanation:
Let us assume the child plate be x
And, the adult plates be y
Now according to the question
x + y = 280 .................(1)
2.60x + 9.50y = 1797.50 .............(2)
Now multiply by 2.60x in equation (1)
2.60x + 2.60y = 728
2.60x + 9.50y = 1797.50
-6.90y = -1069.50
y = 155
So, x = 280 - 155
= 125
hence, the number of child plates and adults plates were served is 125 and 155 respectively