To answer this question you have to create a system of equations. The first equation will be that Devi's money (x) equals her brother's money (y), or x = y. The next equation would be that (3/5)x + (7/10)y = 78. You than can substitute x in for y because x = y. The equation would know be (3/5)x + (7/10)x = 78. You then combine the like terms to create an equation of (13/10)x = 78. Then, multiply both sides by 10 / 13 in order to isolate x. This will create the equation x = 60. This means that Devi and her brother each had 60 dollars. You then find out how much they spent and add it together. You can do so with the equation (2/5)x + (3/10)y = z, with z being total money spent. You substitute 60 in for x and for y then solve. When you solve you see that 24 + 18 = z, or that z equals 42. In other words, they spent 42 dollars altogether.
It’s simple, do: 8+8+10+10, just add them you will get 36. The explanation is: Perimeter is add up all the sides, since it is a rectangle it has congruent sides, so they have the same length
Your answer will be 1/55 or A because, at the beginning of the problem it states "you are one of 55 people" ((:
Plug in 4 for x and solve equation like so. c=2
