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Question
primary 5 | Maths
| Whole Numbers
2 Answers Below
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Thank uu
Date Posted: 2 years ago
Views: 528
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done
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clear
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Do a systematic listing
Date Posted:
2 years ago
Oh thank you so mich !
Alternative and faster approach to listing, using logic :
① Multiples of 5 end with either a 0 or a 5.
(Eg. 5,10,15,20,25,... and so on)
So, in 2 years' time, the age will end with a 2 or 7.
② Since Tim's age in 2 years' time is a multiple of 11, then only the number 22 will satisfy the conditions (we do not consider 77 since he is less than 60 years old)
Current age = 22 - 2 = 20
③ Check :
Tim's age in 1 year's time = 21 (which is a multiple of 3 since 21 = 3 × 7)
① Multiples of 5 end with either a 0 or a 5.
(Eg. 5,10,15,20,25,... and so on)
So, in 2 years' time, the age will end with a 2 or 7.
② Since Tim's age in 2 years' time is a multiple of 11, then only the number 22 will satisfy the conditions (we do not consider 77 since he is less than 60 years old)
Current age = 22 - 2 = 20
③ Check :
Tim's age in 1 year's time = 21 (which is a multiple of 3 since 21 = 3 × 7)
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