The Empirical Rule affirm:
99.7 % random variable values are between
±
three standard deviation.
95 % random variable values are between
±
two standard deviation.
68 % random variable values are between
±
one standard deviation. There you go!
Let C be the amount of compost
T be the amount of topsoil
Each compost cost = $25
Cost of C compost = 25C
Each topsoil cost = $15
Cost of T topsoil = 15T
Amount of compost + amount of topsoil = 10
C + T = 10 -------> Equation 1
cost of C compost + cost of T topsoil = 180
25C + 15T = 180 --------> equation 2
Solve the first equation for C
C + T = 10
C = 10 - T
Now plug it in second equation
25C + 15T = 180
25 ( 10 - T) +15T = 180
250 - 25T + 15T = 180 (combine like terms)
250 - 10 T = 180 (Subtract 250 on both sides)
-10T = 180 - 250
-10T = -70 ( divide by -10 on both sides)
T = 7
She purchased 7 cubic yards of topsoil .
The sum would end us as: 2.33333333
Okay so every triangle will have 3 angles that add to 180 degrees. You are given that A=65 which means that B + C will have to add to 115. You are given that B= (3x-10) and C=2x, plug this into B+C=115. So
3x-10+2x=115, isolate x, 5x=125, divide both sides by 5 and you get that x=25. This makes B=65, and C=50. Just to check, if you add these together you get 180 degrees.
