Question

A cup of tea costs $3.25 at a local cafe. Alan and his wife, Patty, have a coupon for $1 off their order. Alan says the expression 3.25t - 1 represents the cost for t cups of tea. Patty says the expression 3t + (-1) represents the cost. Are their expressions equivalent? Explain.

Answer 1

Explanation:

The expressions are not equivalent. A cup of tea costs $3.25. $3.25t reprensents the total cost for the number of cups of tea (t) in one order. Subtracting the $1 coupon or adding the coupon as a negative results in the same discount. But Patty is using the wrong cost for a cup of tea, $3 instead of $3.25. Resulting in expressions that are NOT equivalent.