For the first 60 positive integers, a = 1, n = 60, l = 60.
Sn = n/2(a + l)
s = 60/2(1 + 60) = 30(61)
For the next 60 positive integer, a = 61, n = 60, l = 120
Sum = 60/2(61 + 120) = 30(61 + 120) = 30(61) + 30(120) = s + 3600
Sum of first 120 positive integers = s + s + 3600 = 2s + 3600
Answer:
1. 12 boys,
5. 15 hours
6. 36
Im not so sure on the others, Gl!
Answer:
Step-by-step explanation:
Let x represent the number of stamps from Europe.
Let y represent the number of stamps from Africa.
Let z represent the number of stamps from Asia.
She has 47 stamps in all. This means that
x + y + z = 47 - - - - - - - - - - - 1
The number of African stamps is 2 times the number of Asian stamps. This means that
y = 2z
She has 20 stamps from Europe. Therefore, substituting x = 20 and y = 2z into equation 1, it becomes
20 + 2z + z = 47
3z = 47 - 20 = 27
z = 27/3 = 9
y = 2z = 2 × 9
y = 18
She has 20 stamps from Europe, 18 stamps from Africa and 9 stamps Asia.
Answer:
a
Step-by-step explanation:
put f of x in to the x spot
Answer: a) The function :
f(x) = 5x + 1000
b) f(x) = 2250 dollars
Step-by-step explanation: Please find the attached file for the solution
