We can use the concept of commutative property of addition here. We know that the addition follow the commutative property.
The commutative property of addition is given by

It means, if we change the order, it will not affect the result.
Therefore, using above mentioned property, we can see that
1+7 = 7+1
Hence, if we know the value of 1+7, then we can easily find the value of 7+1 because both are same.
Let s = sale
Let h = hours
The ratio is s to h, which can be written as a fraction as 24/6.
The standard form is 24,000,011
She has a total of 170 cubes
170/10=17 trains