1/1×3+1/2×4+1/3×5 +...+1/18×20=Please, help me. ❣️

Mathematics

1 answer:

Sedaia [141]2 years ago

6 0

Answer:3.1944

Step-by-step explanation:

(1÷1×3)+1÷(2×4)+1÷(3×5)+1÷(18×20)

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A family of 2 adults and 3 children went out to dinner. The total bill was $42. Each child's dinner cost $4. How much did each a

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Answer: Each adult’s meal costed $15

Step-by-step explanation:

This situation can be modeled by the following equation:

2a + 3c = 42, where a = the cost of an adult’s meal, and c = the cost of a child’s meal

Since we know from the problem that a child’s meal costs $4, we know c:

2a + 3(4) = 42

At this point, we can just solve the resulting equation for a:

2a + 3(4) = 42

= 2a + 12 = 42 (simplify 3(4))

= 2a = 30 (subtract 12 from both sides)

= a = 15 (divide both sides by 2)

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Mandarinka [93]

1. Check picture 1. Let the one side of the triangle be a, drop one perpendicular, CD. Then triangle ADB is a right triangle, with hypothenuse a and one side equal to 1/2a. By the Pythegorean theorem, as shown in the picture, the height is $\frac{ \sqrt{3} }{2} a$

2. if a a=25 ft, then the height is $\frac{ \sqrt{3} }{2} a=\frac{ \sqrt{3} }{2} *25= \frac{1.732}{2}*25= 21. 7$ (ft)

3. consider picture 2. Let the length of the roof be l feet.

one side of the prism (the roof) is a rectangle with dimensions a and l, so the area of one side is a*l
the lateral Area of the roof is 3a*l

the area of the equilateral surfaces is $2*( \frac{1}{2} *a* \frac{ \sqrt{3} }{2}a )=\frac{ \sqrt{3} }{2} a^{2}$

so the total area of the roof is $\frac{ \sqrt{3} }{2} a^{2} +3al$

4. The total area was the 2 triangular surfaces + the 3 equal lateral rectangular surfaces. Now instead of 3 lateral triangular surfaces, we have 2.
So the total area found previously will be decreased by al

5. so the area now is $\frac{ \sqrt{3} }{2} a^{2} +2al$

6. now a=25 and l=2a=50

Area= $\frac{ \sqrt{3} }{2} a^{2} +2al=\frac{ \sqrt{3} }{2} * 25^{2}+2*25*50=25 ^{2} (\frac{ \sqrt{3} }{2} +4)=625*4.866$

=3041.3 (ft squared)

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3 years ago

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The height of a free falling object at time t can be found using the function, h(t) = - 12t2 + 36t. Where h(t) is the height in

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For this case we have the following equation:
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- 12t2 + 36t = 0
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t2 = 3
Therefore, the time it takes the object to hit the ground is:
t = 3 s
Answer:
the time when the object hits the ground is:
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