Livia's answer to Rhea's Primary 5 Maths Whole Numbers Singapore question.
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Father:4u-2u=20
2u=20
1u=20÷2
=10
If the father is four times older than Serene,
1u=10
4u=10×4
=40
To check, in 20 years, Serene's Father will be twice her age.
Now:
Serene=10(1u)
Father =40(4u)
In 20 years:
Serene=10+20
=30
Father=40+20
=60
=30×2 (Serene's age ×2)
Hence the Father is now 40 years old.
2u=20
1u=20÷2
=10
If the father is four times older than Serene,
1u=10
4u=10×4
=40
To check, in 20 years, Serene's Father will be twice her age.
Now:
Serene=10(1u)
Father =40(4u)
In 20 years:
Serene=10+20
=30
Father=40+20
=60
=30×2 (Serene's age ×2)
Hence the Father is now 40 years old.
Date Posted:
1 year ago
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