# Which is the better way of framing the solution to this simple math problem?

I was thinking of using this problem for tutoring. I can see two ways of answering it, and I can see advantages to each approach.

Problem
A store buys 10 widgets at \$2 each and sells 8 of them for \$3 each. What is the store’s profit?

Method 1. Total cost is 10 x \$2 = \$20. Revenue from selling 8 is 8 x \$3 = \$24. Profit = \$24 – \$20 = \$4.

Method 2 – Profit from widgets sold is \$1 per widget sold. 8 widgets sold gives profit of 8 x \$1 = \$8. Cost of 2 unsold widgets is 2 x \$2 = \$4. \$8 – \$4 = \$4.

Observing members: 0 Composing members: 0

I like Method 1
Where does it say in the problem that profit is \$1

josie (29098)

I used Method 1 as I was reading the problem.

LuckyGuy (36504)

What if we have 2 widgets bought for \$1, 3 for \$2 and 5 for \$3, all sold for \$5 each? Doesn’t it become easier to add up the profit on each group? Profit = 2 x \$4 + 3 x \$3 + 5 x \$2 = \$27.

I’d go with Method 1. It’s more straightforward and fewer math evolutions.

seawulf575 (7743)

In your later example in my head I thought 2 x \$1 + 3 x \$2 + 5 x \$3 = \$2 + \$6 + \$15 = \$23 spent
and 2 + 3 + 5 = 10, x \$5 = \$50 received. = 50 – 23 = 27 profit.

LuckyGuy (36504)

@josie the cost to buy them is \$2 each. They sell them for \$3 each. That’s your \$1 profit.

I like method 1 too.

Dutchess_III (39689)