RU is 34. To find the answer you can use a proportion. In this problem the proportion would be 60/51 = 40/x. You can then cross multiply giving you 51*40=60x. You can then solve for x which is your answer.
For any arbitrary 2x2 matrices

and

, only one choice of

exists to satisfy

, which is the identity matrix.
There is no other matrix that would work unless we place some more restrictions on

. One such restriction would be to ensure that

is not singular, or its determinant is non-zero. Then this matrix has an inverse, and taking

we'd get equality.
Here are the numbers from least to greatest
1.6,1.65,15/8,7/4
The percent is 145. That should be your answer
Jdurjrjufurjrjrjrurrurjrn it is 6