Sagot :
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1. The difference between 10 times a number and 16 is 74. Find the number.
Equation:
10(n) - 16 = 74
Solution:
74 + 16 = 90,
90 ÷ 10 = 9,
n = 9
Answer:
10 (9) - 16 = 74
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3. A mother is twice as old as her daughter. Five years from now, she will be thrice as old as her daughter. How old is the mother 5 years from now?
Equation:
in present: mother's age = dau. age × 2
in 5 years: mother's age = dau. age × 3
Solution:
dau. age = 5
in present: mother's age = 5 × 2 = 10
in 5 years: mother's age = 5 × 3 = 15
Answer:
it's kind of weird, but I think the mother's age 5 years from now is 15.
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4. Mrs. Co is 45 years old, and her eldest daughter is 21 years old. When will Mrs. Co be 4 less than twice as old as her eldest daughter?
Equation:
Mrs. Co = dau. × 2 - 4
Solution:
the difference between Mrs. Co and daughter's age is 24
and let's say: 7 years from now, dau. age = 21 + 7 = 28
so, Mrs. Co = 28 × 2 - 4 = 52
then, Mrs. Co will be 52 in 7 years from now.
checking: 52 - 28 = 24 (the difference between Mrs. Co and dau. age)
Answer:
In 7 years from now, Mrs. Co will be 4 less than twice as old as her eldest daughter.
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this is one of the most challenging set of questions I've encountered