Answer:
y=92
Step-by-step explanation:
Divided both sides by the numeric factor on the left side, then solve.
y = 92
18 ÷ 3 is 6, which means that Daniel is 6, and there is a 12 year gap between Steve and Daniel.
12 x 2 is 24, so therefore when Steve is 24, Daniel will be 12, so Steve is twice as old as Daniel:)
If 
is a number that is both divisible by 4 and 5, then
4 and 5 are coprime, so we can use the Chinese remainder theorem to solve this system and find that 
is a solution to the system, where 
is any integer. Simply put, any multiple of 20 fits the bill.
Now, there are 11 numbers between 100 and 300 that are divisible by 20 (100, 120, 140, and so on). We have 
when 
, so the sum we want to compute is
