Sheila has x 20 dollar bills, and Tamsin has y 10 dollar bills. Sheila has a total of $50 more than Tamsin, but Tamsin has 1 more bill than Sheila. How many bills does Sheila have?

Sheila have 6 bills

Step-by-step explanation:

Suppose Sheila has x '20' dollar bills, so the total cost of her bill = $20x

Suppose Tamsin has y '10' dollar bills, so the total cost of her bill = $10y

Equation 1

Sheila has a total of $50 more than Tamsin

10y + 50 = 20x

Equation 2

Tamsin has 1 more bill than Sheila.

y = x + 1

Now solve them by putting value of x in equation

10 (x + 1) + 50 = 20x

10x + 10 + 50 = 20x

60 = 20x - 10x

10x = 60

x = 60/10

x = 6

and

y = 7