Answer:
The number of river rent tubes are 11 and the number of cooler tubes are 4.
Explanation:
Given,
Total number of tubes = 15
Total amount of money spent = $270
Price of river rent tube = $20
Price of cooler tube = $12.50
Solution,
Let the number of river rent tube be x.
And the number of cooler tube be y.
So,
Total number of tubes = The number of river rent tube + The number of cooler tube
On substituting the values, we get;

Now,
Total amount of money spent = Price of river rent tube X The number of river rent tube + Price of cooler tube X The number of cooler tube
So,

Now multiplying equation 1 by 20 and then subtract equation 2 from it, we get;



On substituting the value of y in equation 1, we get the value of x;

Thus the number of river rent tubes are 11 and the number of cooler tubes are 4.