Answer:
77.5
Step-by-step explanation:
For 0.30 for the first 50, just subtract 50 from 175, that leaves 125.
(An easy way to do this is think of quarters, 25+25=50 and 50+25=75 so all you have to do is subtract two 25s and you know it's 125)
Put the 125 to the side, and multiply 50 to 0.30, you get 15.
Then for 0.50 over 50 containers, multiply the remaining 125 with 0.50, you get 62.5.
Add 62.5 and 15 together, that gives you 77.5