Answer:the present age of the father is 45 years
Step-by-step explanation:
Let x represent the present age of the father.
Let y represent the present age of the son.
Let z represent the age of the daughter.
A father is 3 times as old as his son. This means that
x = 3y
his daughter is 3 years younger than the son. It means that
z = y - 3
The sum of their ages 3 years ago was 63. This means that
x - 3 + y - 3 + z - 3 = 63
x + y + z - 9 = 63 - - - - - - - - - - 1
Substituting x = 3y and z = y - 3 into equation 1, it becomes
3y + y + y - 3 - 9 = 63
5y - 12 = 63
5y = 63 + 12 = 75
y = 75/5 = 15
x = 3y = 3 × 15
x = 45
z = y - 3 = 15 - 3
z = 12
The surface area of a prism is the total sum of the areas of all sides of the prism.
Answer:
400
Step-by-step explanation:
rounding to the nearest hundred, in bold you'll see the hundred place.
418.953
The number next to that (right side →) determines if it stays 4 or goes one number up, 5.
If it's 4 or lower is stays the same
and
If it's 5 or higher (up to 9) it increases by 1.
so
because the number next to it is a 1, it stays 4.
Therefore 400 is the answer.
Answer:
0.083
Step-by-step explanation:
To solve the above question, we use the combination method.
C(n, r) = nCr = n!/r!(n - r)!
Probability of answering (all 5 correctly)
= Probability of answering ( 5 out of 7 correctly)/ Probability of answering (5 out of 10 problems)
Probability of answering ( 5 out of 7 correctly) = 7C5
nCr = n!/r!(n - r)!
= 7!/5! (7 - 5)!
= 7 × 6 × 5 × 4 × 3 × 2 × 1/( 5 × 4 × 3 × 2 × 1) × (2 × 1)
= 21 ways
Probability of answering (5 out of 10 problems) = 10C5
nCr = n!/r!(n - r)!
= 10!/5! (10 - 5)!
= 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1/( 5 × 4 × 3 × 2 × 1) × (5 × 4 × 3 × 2 × 1)
= 252 ways
Probability of answering (all 5 correctly)
= 21/252
= 0.0833333333
Approximately = 0.083