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1 year ago

Two ladders AB and PQ are resting against opposite

Mathematics

1 answer:

muminat1 year ago

5 0

Answer:

The length of the longer ladder is 35 ft Step-by-step explanation: Please check the attachment for a diagrammatic representation of the problem We want to calculate the length of the longer ladder ; We make reference to the diagram Since the two right triangles formed are similar. the ratios of their sides are equal; Thus; 20/15 = 28/x + 15 20(x + 15) = 15(28) 20x + 300 = 420 20x = 420-300 20x = 120 x = 120/20 x = 6 So we want to calculate the hypotenuse of a right triangle with other sides 28ft and 21 ft To do this, we use the Pythagoras’ theorem which states that square of the hypotenuse equals the sum of the squares of the two other sides Let the hypotenuse be marked x x^2 = 28^2 + 21^2 x^2 = 1,225

x = √1225

x = 35 ft

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Alchen [17]

Step-by-step explanation:

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2 years ago

After spending 30% of her salary Sara was able to deposit $120 in the bank. What is her salary?

Katena32 [7]

Answer: $400

Step-by-step explanation:

So first you set it up in a equation. You put the amount she put in the bank over x (the x represents her full salary) which equals the percent she already spent over her full salary. That would be 120/x=30/100 you would then cross-multiply to get 12,000 = 30x. you then divide 30 from both sides to get x =400.

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2 years ago

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bulgar [2K]

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2 years ago

A junk box in your room contains fourteen old batteries, seven of which are totally dead. You start picking batteries one at a

MrMuchimi

Answer:

A junk box in your room contains fourteen old batteries, seven of which are totally dead.

So, number of good batteries = $14-7=7$

a) The first two you choose are both good.

There is a 7/14 chance that we will pick a good battery.

Now there are 13 batteries left and out of that there are only 6 good ones remaining, so this becomes 6/13.

So, combined probability is = $\frac{7}{14}\times \frac{6}{13}$

= 0.23

b) At least one of the first three works.

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c) The first four you pick all work.

There is a probability of 7/14 for the first one to work, 6/13 for the second, 5/12 for the third and 4/11 when the fourth is good, combined we get by multiplying all:

$\frac{7}{14}\times \frac{6}{13}\times \frac{5}{12}\times \frac{4}{11}=0.0344$

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This condition means that we pick 4 bad batteries and 1 good battery.

The probability of picking 4 bad batteries is -

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