The sum of the two numbers is 80. The sum of 25% of the first number and 40% of the second is 23.
May 5, 2021 | education
| The sum of the two numbers is 80. The sum of 25% of the first number and 40% of the second is 23. Find these numbers.
Take two numbers A and B. It is known that:
A + B = 80;
We express B through A:
B = 80 – A;
Let C be 25% of the number A and D – 40% of the number B:
C = 0.25 * A;
D = 0.4 * B = 0.4 * (80 – A) = 32 – 0.4 * A;
By the condition of the problem:
C + D = 23;
Means:
0.25 * A + (32 – 0.4 * A) = 23;
0.25 * A – 0.4 * A = 23 – 32;
– 0.15 * A = – 9;
A = 9 / 0.15 = 60;
Next, we calculate B:
B = 80 – A = 80 – 60 = 20;
Verification:
0.25 * A + 0.4 * B = 0.25 * 60 + 0.4 * 20 = 15 + 8 = 23;
Answer: the first number is 80; the second number is 20
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