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3 years ago

What is the sum if the first 22 terms of the following series? 86 + 79 + 72 + 65 +58+...

1 answer:

5 0

Seems to be an arythmetic sequence
Sn=[n(a1+an)]/2
where
Sn means sum of all terms up the nth term
n=number of terms
a1=first term
an=nth term

so from 86 to the 22th term is from a1 to a22

find teh sequence
miknus 7 each time
an=a1+d(n-1)
an=87-7(n-1)
find 22n term
a22=87-7(22-1)
a22=87-7(21)
a22=87-147
a22=-60

S22=[22(87-60)]/2
S22=[22(27)]/2
S22=594/2
S22=297

the sum is 297

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shutvik [7]

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3 years ago

Suppose you can work at most a total of 25 hours per week. Baby-sitting, x, pays $6 per hour and working at the grocery store, y

Andrei [34K]

Answer:

y=7 number of hours at grocery store

x=18 number of hours at baby- sitting

Step-by-step explanation:

According to the information provided.

x is number of hours at baby- sitting

y is number of hours at grocery store

total number of hours worked

1) x+y =25

total earn in a week

2) x*$6 + y* $9 = $171

from equation 1

x+y=25

x= 25-y

we place the above derived equation in equation 2

x*$6 + y* $9 = $171

(25-y)*$6 + y* $9 = $171

(25*6) -6y +9y =171

150+3y=171

3y=171-150

3y=21

y=7 number of hours at grocery store

x= 25-y

x= 25-7

x=18 number of hours at baby- sitting

3 0

3 years ago

How to find the slope on a table

bazaltina [42]

M= y2-y1/x2-x1

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2 years ago

A rectangular swimming pool measures 14 feet by 30 feet. The pool is

Zolol [24]

Answer:

The total cost of resurface the path is $\$600$

Step-by-step explanation:

step 1

Find the area of the path

The area of the path is equal to the area of the path plus the swimming pool minus the area of the swimming pool

$A=(14+3+3)(30+3+3)-(14)(30)$

$A=(20)(36)-(14)(30)$

$A=300\ ft^{2}$

step 2

Find the cost of resurface the path

Multiply the area of the path by $2 per square foot

$300*2=\$600$

4 0

3 years ago

Teboho has to sell a certain number of cars each month. For every car he sells over and above this number he earns 17% commissio

Nastasia [14]

The commission earned are R41123.17, R47931.67 and R15024.09

<h3>The prices of the cars before VAT was added</h3>

The VAT included prices are given as:

R271 800,00; R316 800,00 and R99 300,00.

The VAT rate is 12.36%.

So, the price before VAT is calculated as:

VAT included = Price without VAT * (1 + 12.36%)

This gives

VAT included = Price without VAT * 1.1236

So, we have:

Price without VAT = VAT included/1.1236

For the three cars, we have:

Price without VAT = R271 800.00/1.1236 = R241901

Price without VAT = R316800.00 /1.1236 = R281951

Price without VAT = R99300.00/1.1236 = R88377

Hence, the prices of the cars before VAT was added are R241901, R281951 and R88377

<h3>The commission he earned on the cars.</h3>

This is calculated as:

Commission = Price * 17%

So, we have:

Commission = R241901 * 17% = R41123.17

Commission = R281951 * 17% = R47931.67

Commission = R88377 * 17% = R15024.09

Hence, the commission earned are R41123.17, R47931.67 and R15024.09