Hey there! I'm happy to help!
Tom has 150 already saved and for every hour he works, he will gain an extra $25. After h hours, he will have $300,
So, we multiply 25 by n, because for every hour he will have 25 added to his total, and repeated addition is multiplication, so we multiply 25 by n.
We add 150 as that is what we already have saved.
Finally, we want this to equal 300.
So, here is our equation.
25n+150=300
Now we solve. We subtract 150 from both sides.
25n=150
We divide both sides by 25.
n=6
Tom will have to work six hours to buy the iPhone.
Have a wonderful day! :D