3+2=5, 3-2=1  The pattern: Pip move forward 1m in 5 steps  $$100-3=97$$  $97\times5+3=488$ 
After every $$3$$ steps that Pip takes forward, he takes $$2$$ steps backwards. Each step is $$1 $$$$\text{m}$$. Pip starts at one end of a $$100$$ $$\text{m}$$ hall. Pip will first reach the other end after~\uline{~~~~~~~~~~}~steps. 
Options:
a) $$100$$ 
b) $$488$$ 
c) $$490$$ 
d) $$500$$ 