Equations and Word Problems Examples

Tickets to a concert cost $25.00 each, including tax. Xavier has $150.00 and wants to get tickets for himself and some friends. How many friends can he invite?

We first write this as an equation and then solve. The total cost is $150, which equals the product of the number of tickets, t, and the cost per ticket, $25.

150 = 25t

Solving for t, we get 150 divided by 25.

Xavier can buy 6 tickets total (including one for himself), so he can invite 5 friends.

Ahmed buys some shoes online for $32.00 per pair including tax, and the shipping is $4.00. If he decides to buy more pairs of those same shoes and it doesn't change the shipping cost, how many can he buy with $100.00?

Ahmed is gonna buy x pairs of shoes, each costing $32.00, so we can write that as a product.

32x

Adding on shipping costs, we get:

32x + 4

And this needs to total $100.00.

32x + 4 = 100

We subtract 4 from both sides and then divide by 32.

Nice. He can buy 3 pairs of shoes.

A plant is 13 inches tall and grows 2 inches a week. How many weeks will it take for the plant to be 23 inches tall?

Man, somebody sure has a green thumb.

We add the current height of the plant to the product of the rate it's growing per week (2 inches) and the number of weeks it grows (n) and set this equal to 23. Then we solve for n.

Translated into math, that gives us the equation:

13 + 2n = 23

Subtracting 13 from both sides, we get: 

 13 + 2n – 13 = 23 – 13 

2n = 10

Divide both sides by 2 and we get n = 5. In 5 weeks the plant will be 23 inches tall. We're gonna need a bigger pot.