If chris has 2 times as many nickels as quarters and they have a combined value of 210 cents, how many of each coin does he have?

Let Q represent Quarters
N represent Nickels
We know that Quarters worth 25 cents
Nickels worths 5 cents
If Chris has 2 times as many nickels as quarters means that
N=2Q
Next,
They have a combined value of 210 cents, so
0.25Q+0.05N=210
Substitute N with 2Q
0.25Q+0.05(2Q)=210
0.25Q+0.10Q=210
0.35Q=210
Divided 0.35 to each side
0.35Q/0.35=210/0.35
Q=600 coins
N=2Q
N=2(600)
N=1200 coins. As a result, Chris has 1200 nickels and 600 quarters. Hope it help!

your answer should be C because obtuse means above 90 but below 180