help me with this pls

Answer:
15
Step-by-step explanation:
** For some reason, it won't let me add the first sentence, as it thinks there are swearwords?? So I have taken a screenshot and attached it.**
Now we just have to solve to find [tex]C[/tex]
[tex]F'=F+1[/tex]
[tex]2C+30=\frac{9}{5} C+32+1[/tex]
[tex]\frac{1}{5} C=3[/tex]
[tex]C=15[/tex]
To confirm, substitute [tex]C = 15[/tex] into:
[tex]F=\frac{9}{5} \times 15 + 32 = 59[/tex]
[tex]F'=2 \times 15 + 30 = 60[/tex]
So when [tex]C=15[/tex], [tex]F'[/tex] is one more than [tex]F[/tex].