On Sunday, Xiaoming went on a trip with seven classmates and eight people. On the way, he bought drinks with 20 yuan money. There is only coke and milk tea in the store, but I know there is a cup of c

On Sunday, Xiaoming went on a trip with seven classmates and eight people. On the way, he bought drinks with 20 yuan money. There is only coke and milk tea in the store, but I know there is a cup of coke, 2 yuan. Four cokes and four milk teas.

Let the number of people who drink coke be x and the number of people who drink milk tea be Y~

2X+3Y=20

X+Y=8

Y=8-X

2X+3(8-X)=20

2X+24-3X=20

X=24-20=4

Y=8-4=4