This is a simple equation.
The equation is y = 1.6x with y being the miles and x being the kilometers.
Lets plug the kilometers in.
Y=1.6(7.7)
1.6 * 7.7 = 12.32
12.32 miles is equal to 7.7 kilometers
HOWEVER
There are about .6 miles in a kilometer, so if you typed this wrong I don't know.
It is still the same concept.
Y = .6x
Y = .6(7.7)
.6 * 7.7 = 4.8
In this case there are 4.8 miles in 7.7 kilometers