A number plus 25% of it equals 6.4. What's the number What's the product of 2.5 minus one fifth and multiplying by eleven thirty-five

A number plus 25% of it equals 6.4. What's the number What's the product of 2.5 minus one fifth and multiplying by eleven thirty-five

Let this number be X,
x+0.25x=6.4
1.25x=6.4
x=5.12