The sum of two numbers is 8 and 15 times the sum of their reciprocals is also 8. Find the numbers.
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Answered by
27
SOLUTION :
Given : The sum of two numbers is 8 and 15 times the sum of their reciprocals is also 8.
Let the numbers x and (8 - x) .
A.T.Q
15(1/x + 1/(8 - x) ) = 8
15[(8 - x) + x]/ x(8 -x) = 8
[By taking LCM]
15[(8 - x) + x]/ (8x - x²) = 8
15(8) = 8(8x - x²)
120 = 64x - 8x²
8x² - 64x +120 = 0
8(x² - 8x + 15) = 0
x² - 8x + 15 = 0
x² - 5x - 3x + 15 = 0
[By middle term splitting method]
x(x - 5) - 3(x - 5) = 0
(x - 5) (x - 3) = 0
(x - 5) = 0 or (x - 3) = 0
x = 5 or x = 3
Hence, the two numbers are 5 & 3 .
HOPE THIS ANSWER WILL HELP YOU..
Answered by
7
Answer is ---
3, 5
Explanation:
Let's call the two numbers x and y.
We're told that x+y=8
We're also told that 15 times the sum of their reciprocal is also 8. I'll interpret what this says this way:
15(1x+1y)=8
We have two equations and two variables, so we should be able to solve this. Let's first solve the first equation for x:
x=8−y
And now substitute into the second equation:
15(18−y+1y)=8
18−y+1y=815
18−y(yy)+1y(8−y8−y)=815
yy(8−y)+8−yy(8−y)=815
8y(8−y)=815
Notice that with the numerators equal, we can say:
y(8−y)=15
8y−y2=15
y2−8y+15=0
(y−3)(y−5)=0⇒y=3,5
And by substituting these values back into our first equation, we get that x=5,3
Now let's check our answer:
15(1x+1y)=8
15(13+15)=8
15(515+315)=8
15(815)=8
8=8
hope it is helpful
please mark me as brainliest
3, 5
Explanation:
Let's call the two numbers x and y.
We're told that x+y=8
We're also told that 15 times the sum of their reciprocal is also 8. I'll interpret what this says this way:
15(1x+1y)=8
We have two equations and two variables, so we should be able to solve this. Let's first solve the first equation for x:
x=8−y
And now substitute into the second equation:
15(18−y+1y)=8
18−y+1y=815
18−y(yy)+1y(8−y8−y)=815
yy(8−y)+8−yy(8−y)=815
8y(8−y)=815
Notice that with the numerators equal, we can say:
y(8−y)=15
8y−y2=15
y2−8y+15=0
(y−3)(y−5)=0⇒y=3,5
And by substituting these values back into our first equation, we get that x=5,3
Now let's check our answer:
15(1x+1y)=8
15(13+15)=8
15(515+315)=8
15(815)=8
8=8
hope it is helpful
please mark me as brainliest
icecreamlover7:
10th
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