Video Transcript
The total cost of a skateboard and
knee pads is 247 dollars. If the skateboard costs 235
dollars, write an equation to find the cost of the kneepads, 𝑘. Then solve the equation.
The problem is asking us to do two
things, write an equation and then solve the equation that we write. We’re given three different pieces
of information. The total cost is 247 dollars. The skateboard costs 235
dollars. And the missing cost, the cost that
we don’t know, is 𝑘, and that’s the cost of the kneepads. We know that the total cost equals
the skateboard price plus the kneepads price. Let’s substitute these two pieces
with the information that we already know. Total cost is 247. Skateboard costs 235. What should we put here for the
knee pads price? Because we don’t know the knee pads
price, we need to substitute a variable here. In our case, that’s where the 𝑘
goes. Our equation becomes 247 equals 235
plus 𝑘.
Step one of the problem is
complete. This is an equation we can use to
solve step two. And this part can be done
mentally. What added to 235 would equal
247? Well, if you add ten, you get from
235 to 245 add two more to that and now you’re at 247. Put both of those numbers you added
together, 10 and two, and you realise that 𝑘 must be equal to 12. 𝑘 is equal to twelve. And that means the kneepads cost 12
dollars. Our final answer here is 𝑘 equals
12 dollars.
