Step-by-step explanation:
3y+5<10
3y<10-5
3y<5
y<⅗
Let's say the numbers are "a" and "b"
thus

set the derivative to 0, and check the critical points, there's only one anyway
and do a first-derivative test, to see if it's a maximum
20% of 124.95 is close to $125 so that is equal of 12.50 of 10% so multiply by 2 which is $25.00 so the estimate discount of the jacket will be $25.00
If you have questions, feel free to ask
8) v=1/3 x 6^2 x 11
= 132cm^3
10) 80ft^3
11) 72km^3
Hope this helps!!