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:
4.25-5 minutes
Step-by-step explanation:
Its shown in the graph and table that the speed was 0 between those times.
Answer:
y = 65
Step-by-step explanation:
45 + 57 = x + y
x = 37
45 + 57 = 37 + y
45 + 57 = 102
102 = 37 + y
102 = 37 + y
-37 -37
102 - 37 = 65
37 + y - 37 = y
65 = y
y = 65
Answer:
Negative 7.9
Step-by-step explanation:
-7.9 is just negative 7.9.
Do you need this as fraction? If you do, I can help ^^
