Question

Some bikes and trikes are on the playground. There are 7 seats and 19 wheels. How many bikes are there? How many trikes are there? Show your work.

Answer 1

1 bike = 2 wheels, one seat 
so 19 /2 =9.5 =9 wheels 
4 bikes 
one tricycle = 3 wheels one seat 
6 trikes

Answer 2

Okay here we go!
1. I'm a visual person so i would start by drawing circles for the wheels. 
o o o o o o o o o o o o o o o o o o o 
2. I tried separating them by threes
ooo ooo ooo ooo ooo ooo o
2 By two's 
oo oo oo oo oo oo oo oo oo o
3. then i started to count 
ooo ooo ooo ooo ooo = 15 and i still had 4 left over 
oo oo = 4 and that would equal to 19 wheels!

the answer is: there are 5 trikes and 2 bicycles!!!!!
Hope that helped!
:)