Jeff received 280$ from his mother
Such questions are the simplest as it needs you to just write the conditions accordingly which then simplifies and provides you the answer.
This question can be solved using two tricks which are shown below:-
Trick 1 :
1 – 1/4 = 3/4 (used for the 1st 7 days)
1/4 – 410 (used for 8th and 9th days)
(3/4)/7 ——- (1/4 – 10)/2
(3/4) x (2/7) = 3/14 ——- (1/4 – 10)
1/4 – 3/14 = (7 – 6)/28 = 1/28 ——- 10
28/28 ——- 10 x 28 =$ 280
Trick 2 :
7 days ——- 3/4
1 day ——- 3/28
2 days ——- 6/28
6/28 ——- (1/4 – 10) = 7/28 – 410
1/28 ——- 10
28/28 ——- 10 x 28 = $280
Thus Jeff received 280$ from his mother.
Learn more about simple math here :
brainly.com/question/23678
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A perpendicular bisector forms two right angles and splits the line in two equal parts.
The altitude does create two right angles, but doesn't have to create two equal parts.
Answer:
It takes 75 years for the investment to quadruple in value
Step-by-step explanation:
Simple Interest
This is a simple interest problem.
The simple interest formula is given by:

In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.
After t years, the total amount of money is:

In this question:
4% simple interest per year, so I = 0.04.
Quadruple:
t when T = 4P.
The interest earned is:



Now we find the time.





It takes 75 years for the investment to quadruple in value
2/21or ethier 2/7 tht will be the answer maybe.
900 divided by 3 is 300 so 300 students bring their lunch opposed to 600 students who do not.