Answer:
Sister = 15 years old
Brother = 12 years old
Step-by-step explanation:
Right now, if the brother is B years old and the sister is S years old, B = (4/5)S because the ratio from brother to sister is 4:5, so if one unit is X, B = 4X and S = 5X
Three years ago, the brother was B-3 years old and the sister was S-3 years old. Keeping one unit as X, we have
B = 3X
S = 4X
B-3 = (3/4)(S-3)
Therefore, we have a system of equations
B = (4/5)S
B-3 = (3/4)(S-3)
Substitute (4/5)S for B into the second equation to only have one variable
(4/5)S - 3 = (3/4)(S-3)
(4/5)S - 3 = (3/4)S - 9/4
add 3 to both sides and subtract (3/4)S from both sides to isolate the variable and its coefficient
(1/20)S = 3/4
multiply both sides by 20 to isolate the S
S = 15
B = (4/5)S = 12
Answer:
0.205177 mi
Step-by-step explanation:
Step 1: Find conversions
12 in = 1 ft
5280 ft = 1 mi
Step 2: Use Dimensional Analysis

0.205177 mi
Answer:
I think 5 and 5 are equal so the angles are equal which are 70,70
Step-by-step explanation:
70+70+x=180
140+x=180
x=40
Answer:
4 hours
Step-by-step explanation:
15 x 4 = 60
$60
Answer:
3,-3
Step-by-step explanation:
g(3)= (3)³+6(3)²-9(3)-54
= 27+54-27-54
=81-81
= 0
g(-3) = (-3)³+6(-3)²-9(-3)-54
= -27+54+27-54
= 27-27
= 0
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