We can solve this problem by the rule of three.
1000 protons=10³ protons
1 proton------------------2.53*10⁻³⁷g
10³ protons---------- x
x=(10³ protons * 2.53*10⁻³⁷) / 1 proton=2.53*10⁻³⁷⁺³ protons=
=2.53*10⁻³⁴ protons
answer: 2.53*10⁻³⁴ protons
If it can scan 72 photos in 8 minutes, it can scan 72/8 = 9 photos per minute.
So in 23 minutes, it can scan 9x23 = 207 photos
Subtract the second equation from double the first equation:
2x+6y-2x-(-4y)=0
10y=0
Therefore, y=0. Substituting this into the first equation, we see that:
x+3(0)=3
x=3
Therefore, x=3. The solution to this system is x=3, y=0, or (3, 0).