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:
The circumference of a circle is equal to π , which is a number ≈3.14 , multiplied by the diameter of the circle. Therefore ... We also know that the diameter has twice the length of the radius. In equation form: 2r=d. 2r=16. r=8. Note that since 2r=d , the equation C=2πr holds and can be used in place of C=πd .
Step-by-step explanation: The circumference of a circle is equal to π , which is a number ≈3.14 , multiplied by the diameter of the circle. Therefore ... We also know that the diameter has twice the length of the radius. In equation form: 2r=d. 2r=16. r=8. Note that since 2r=d , the equation C=2πr holds and can be used in place of C=πd .
Answer:
4.5
Step-by-step explanation:
The formula for solving area in parallelograms is base x height.
The base is 2.5 and the height is 1.8
2.5x1.8=4.5
Answer:
x<±1 and x< -3
Step-by-step explanation:
Given the inequality x^2-1/3x+9<0, we are to find the values of x that satisfies the inequality
x^2-1/3x+9<0
x^2-1/3x+9 (3x+9)²<0* (3x+9)²
(x^2-1)(3x+9) < 0
x²-1 < 0 and 3x + 9 <0
x²-1 < 0
x²<1
x<±√1
x<±1
Also 3x + 9 <0
3x < -9
x < -9/3
x < -3
Hence the required values of x are x<±1 and x< -3
