t = cost of toast, b = cost of bagel, m = cost of muffin

2t + b = 3.15 Equation 1

b + m = 3.5 Equation 2

t + 2b + 3m = 8.15 Equation 3

Use elimination:

2*Equation 3 - Equation 1:

2t + 4b + 6m - 2t - b = 16.3 - 3.15; 3b + 6m = 13.15 Equation 3.1

6*Equation2 - Equation 3.1:

6b + 6m - 3b - 6m = 21 - 13.15

3b = 7.85

b = 261.666666666... cents

So, **a bagel costs (roughly) 262 cents.**