5$ to get in and 0.80 to ride but he can only spend 25$ how many rides can he get on

When you arrive at the lake, your friend realises he hasn’t got any swimming trunks. you need to ride to a sports shop. the sports shop is 8350 metres away. how many metres is it to cycle there and back?

Can some one me with these questions

Explain how you can find the missing fraction in 3 4/5 / (blank) 2 5/7. then find the missing fraction.