Part A #2: The students paid 25% of their earnings to the company after raising $240. 25% of $240 is $60, so thats how much they paid to the company. Because they lost $60, they now need to get $50 more dollars to get the amount they need. If they kept the $60, they wouldn't have had to pay $50 more dollars.
Part B #1: Since $50 plus 75% (.75) of the original amount, $240, makes the amount of money the students need in all, set it up as equal to m. So:
m=240(.75)+50
Part B, #2: Simply solve the equation from #1.
m=240(.75)+50
Following order of operations, solve the multiplication part first.
m=180+50
And finally add.
m=$230
So the students needed to raise $230 for their field trip. This proves Part A, #2 (if the students hadn't needed to give 25% to the company, they wouldn't need any more money since they originally made $240--$10 more than what they needed.)
Hope that helped :)
