mary is twice older than her sister. in 5 years time ,she will be 2years older than her sister.Find how old are they both now.Explain this answer plz...
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Answered by
6
lets suppose sister is x old
mary 2x year old
after 5 years
suppose present age is 2 of sister
sister=5+2=7
marry 5 + 2×2=5+4=9
finish
mary 2x year old
after 5 years
suppose present age is 2 of sister
sister=5+2=7
marry 5 + 2×2=5+4=9
finish
param4:
so suppose marry is 4year old
sister 2 year old
after 5 year marry will 2x +5 =7
sister will x+5= 5
thats all
Answered by
11
Let us assume, Mary's present age is x years and her sister's age is y years.
Given:
x = 2y ------------1
After 5 years,
x + 5 = y + 5 + 2
x + 5 = y + 7
x - y = 2 --------------2
Substitute x = 2y from equation 1 in equation 2
2y - y = 2
y = 2 years
Therefore x = 2y = 2 * 2 = 4 years.
Mary's present age is 4 years and her sister's age is 2 years.
Given:
x = 2y ------------1
After 5 years,
x + 5 = y + 5 + 2
x + 5 = y + 7
x - y = 2 --------------2
Substitute x = 2y from equation 1 in equation 2
2y - y = 2
y = 2 years
Therefore x = 2y = 2 * 2 = 4 years.
Mary's present age is 4 years and her sister's age is 2 years.
thank u very much
its ok
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