He brought 60$. The cost of 12 spinners all together is 10 dollars. Ibon bought 6 times that, because 10 dollars is only a sixth of what he brought. 60/6 is 10, and 60 x 1/6 is 10.
To find the unit rate of a given amount, you have to divide the price by the fluid oz or amount. In this case it is 1.19 / 12. The quotient is 0.0991666667 or (rounded) $0.10.
