Let, number of children and adults swam at the public pool that day is x and y.
So, x + y = 379 .....1)
It is given that daily prices are $1.75 for children and $2.00 for adults.
Also, the receipts for admission totaled $693.50.
So, 1.75x + 2y = 693.50 .....2)
Putting value of y from equation 1 to equation 2 , we get :
1.75x + 2( 379 - x ) = 693.50
758 - 2x + 1.75x = 693.50
0.25x = 64.5
x = 258
So, y = 379 - 258 = 121
Therefore, number of children are 258 and adults are 121.