there is a certain period of number such that the sum of the twice the first number and thrice the second number is 61 however when we subtract 5 times the second number from four time the first number the answer is a 45 find the numbers
Answers
Answer . . .
Numbers = 20 and 7
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Let the -
- first number = x
- second number = y
Sum of the twice the first number and thrice the second number is 61.
According to question,
2(x) + 3(y) = 61
2x + 3y = 61 ...(1)
Also, said in question that
Subtract 5 times the second number from four times the first number the answer is 45.
According to question,
4(x) - 5(y) = 45
4x - 5y = 45 ...(2)
Multiply (eq 1) with 2
→ 2x + 3y = 61 (×2)
→ 4x + 6y = 122
→ 4x = 122 - 6y ...(3)
Substitute value of 4x in (eq 2)
122 - 6y - 5y = 45
- 11y = 122 - 45
- 11y = - 77
y = 7
Substitute value of y in (eq 1)
2x + 3(7) = 61
2x + 21 = 61
2x = 61 - 21
2x = 40
x = 20
•°• First number = x = 20 and Second number = y = 7
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Verification:-
From the above calculations x = 20 and y = 7
Substitute value of x and y in (eq 1)
→ 2(20) + 3(7) = 61
→ 40 + 21 = 61
→ 61 = 61
Similarly, substitute value of x and y in (eq 2)
→ 4(20) - 5(7) = 45
→ 80 - 35 = 45
→ 45 = 45
Numbers are 20 and 7.
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Let the numbers be p and q.
1st condition : The sum of the twice the first number and thrice the second number is 61.
2p + 3q = 61 _______(i)
2nd condition : when we subtract 5 times the second number from four time the first number the answer is a 45.
4p - 5q = 45 ________(ii)
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Multiply equation (i) by 2 and equation (ii) by 1.
{ 2p + 3q = 61 } × 2
{ 4p - 5q = 45 } × 1
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4p + 6q = 122
4p - 5q = 45
By subtracting, we get,
11q = 77
q =
q = 7
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Now, put the value of q in eq (i)
2p + 3(7) = 61
2p + 21 = 61
2p = 61 - 21
2p = 40
p =
p = 20
Numbers are 20 and 7.
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We get,
p = 20 and q = 7
Put the above values in equation (i).
2p + 3q = 61
2(20) + 3(7) = 61
40 + 21 = 61
61 = 61
Hence verified!