2 / 1: x = 4 / 1:10 / 1 is 2:1: x = 4:1:10:1 how to calculate? How much is it equal to?

2 / 1: x = 4 / 1:10 / 1 is 2:1: x = 4:1:10:1 how to calculate? How much is it equal to?

2:1 multiplied by 10:1 and divided by 4:1 is 5:1