AC Lim's answer to John's Primary 5 Maths Singapore question.
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Age different are same throughout the life. Refer to comments for more explanation. Hope this helps
Date Posted:
4 years ago
When father 42 years old,
son =2u
daughter =1u.
Hence, age different for son and daughter 2u-1u =1u.
① Father and son age different = 42-2u
When daughter is 27 years old,
son's age will be u + 27 (cause age different is u),
father is twice his son's age, therefore, father age
= u + 27 + u + 27
= 2u+54.
② Father and son age different
2u+54-u-27
=u+27
①=② cause age different are same.
42-2u=u+27
3u=15
u=5 ....
Hope this helps
son =2u
daughter =1u.
Hence, age different for son and daughter 2u-1u =1u.
① Father and son age different = 42-2u
When daughter is 27 years old,
son's age will be u + 27 (cause age different is u),
father is twice his son's age, therefore, father age
= u + 27 + u + 27
= 2u+54.
② Father and son age different
2u+54-u-27
=u+27
①=② cause age different are same.
42-2u=u+27
3u=15
u=5 ....
Hope this helps
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