The number of permutations of the 4 different letters, taken two at a time, is given by:
Usually you are given more information about the rectangle such as distance of length in terms of width.
You know that the formula for perimeter is
P=2(l+w)
Substitute p and the other values to find width.
Hope I helped :)
#2
Change mixed numbers to improper fractions. Then change division to multiplication by the reciprocal.
1 1/2 divided by 3/5=
(3/2) * (5/3) = 5/2 = 2 1/2
#3
(5/9) divided by (5/3)
(5/9) * (3/5) =3/9 = 1/3
50+ 7.99 x =y
50+ 7.99 (40)= y
50+319.60= y
369.60=y
50+ 7.99 x =y
50 + 7.99 (50)
50+ 399.50=449.50
6.99(30)=209.70
449.50 + 209.70 =659.2