Dalia C. answered • 01/18/17

Tutor

4.8
(31)
Highly Qualified Mathematics and Physics for grades 7-12 in CT.

problem 1:

let s be the side of the square

let l be the length of the rectangle

let w be the width of the rectangle

then,

s

^{2}=l*w+3, the area or the square is 3 inches longer than the area of the rectangle.w=s-3, the width of the rectangle is 3 inches shorter than the side of the square.

l=s+4, the length of the rectangle is 4 inches longer than the side of the square.

if you substitute the s values of l and w into the area equation,

s2=(s-3)(s+4)+3, solving this give the side of the square,

s=9.

You should be able to now calculate the length and width of the rectangle.

problem 2:

let v = the speed of the boat

let vs = the speed of the stream

let t = time of trip

let x

_{d}= distance covered downstream during time tlet x

_{u}= distance covered upstream during time tfor the downstream trip, the distance covered is due to the speed of the boat and the speed of the stream, or:

x

_{d}=(v+vs)*tfor the the trip upstream the distance covered is due to the speed of the boat less the speed of the stream, or:

x

_{u}=(v-vs)*tsolve both equations for t, and set the equal to each other to get

20*(v-v

_{s})=12*(v+v_{s}),solve for v

_{s}.