The sum of the age of father and son is 99.if the age of the son is added to the inverted age of the father,the sum is 72.if the inverted age of the son is subtracted from the age of the father.the difference is 28...what are there age?
plz help i do not no it at all show working!!
5 answers
what is an "inverted age"?
Aldo ur english beat me but anything i guess inverted means inverse
such that let father=f and son=s
let the age of father be=10f+s
inverted age now will be=10s+f
99-(10f+s)=age of son
inverted age now will be=90-10s)+(9-s)...because there sre still d same i jus do dat to help we my addition
now
we add
10f+s+90-10s+9-f=72
9f-9s=72
divide tru by 9
f-s=3.........(a)
and
10s+y-(90-10y)-(9-s)=22
10s+f-90+10f-9+s=22
11s+11f=121
s+f=11.......(b)
bring a and b togeda
f-s=3
s+f=11
rearrange
-s+f=3
s+f=11
2f=14
f=7
puttin 7 into a
s+7=11
s=4
so father is =10y+4
10*7+4=74
AND SON
99-20-4=25
check since fs=74 sf=47 son is either inverted 52
47+25=72
72=72
74-52=22
22=2
am i correct sir steve
such that let father=f and son=s
let the age of father be=10f+s
inverted age now will be=10s+f
99-(10f+s)=age of son
inverted age now will be=90-10s)+(9-s)...because there sre still d same i jus do dat to help we my addition
now
we add
10f+s+90-10s+9-f=72
9f-9s=72
divide tru by 9
f-s=3.........(a)
and
10s+y-(90-10y)-(9-s)=22
10s+f-90+10f-9+s=22
11s+11f=121
s+f=11.......(b)
bring a and b togeda
f-s=3
s+f=11
rearrange
-s+f=3
s+f=11
2f=14
f=7
puttin 7 into a
s+7=11
s=4
so father is =10y+4
10*7+4=74
AND SON
99-20-4=25
check since fs=74 sf=47 son is either inverted 52
47+25=72
72=72
74-52=22
22=2
am i correct sir steve
Aldo d beat me but anything i guess inverted means inverse
such that let father=f and son=s
let the age of father be=10f+s
inverted age now will be=10s+f
99-(10f+s)=age of son
inverted age now will be=90-10s)+(9-s)...because there sre still d same i jus do dat to help we my addition
now
we add
10f+s+90-10s+9-f=72
9f-9s=72
divide tru by 9
f-s=3.........(a)
and
10s+y-(90-10y)-(9-s)=22
10s+f-90+10f-9+s=22
11s+11f=121
s+f=11.......(b)
bring a and b togeda
f-s=3
s+f=11
rearrange
-s+f=3
s+f=11
2f=14
f=7
puttin 7 into a
s+7=11
s=4
so father is =10y+4
10*7+4=74
AND SON
99-20-4=25
check since fs=74 sf=47 son is either inverted 52
47+25=72
72=72
74-52=22
22=2
am i correct sir steve
such that let father=f and son=s
let the age of father be=10f+s
inverted age now will be=10s+f
99-(10f+s)=age of son
inverted age now will be=90-10s)+(9-s)...because there sre still d same i jus do dat to help we my addition
now
we add
10f+s+90-10s+9-f=72
9f-9s=72
divide tru by 9
f-s=3.........(a)
and
10s+y-(90-10y)-(9-s)=22
10s+f-90+10f-9+s=22
11s+11f=121
s+f=11.......(b)
bring a and b togeda
f-s=3
s+f=11
rearrange
-s+f=3
s+f=11
2f=14
f=7
puttin 7 into a
s+7=11
s=4
so father is =10y+4
10*7+4=74
AND SON
99-20-4=25
check since fs=74 sf=47 son is either inverted 52
47+25=72
72=72
74-52=22
22=2
am i correct sir steve
I guess by inverted you mean the digits are switched.
So, if the father's age is xy and the son's age is ab, then we have
10x+y+10a+b=99
10a+b+10y+x=72
10x+y-(10b+a)=28
http://www.wolframalpha.com/input/?i=solve+10x%2By%2B10a%2Bb%3D99%2C+10a%2Bb%2B10y%2Bx%3D72%2C+10x%2By-%2810b%2Ba%29%3D28
If you look at the solution (undetermined, since we have only 3 equations and 4 unknowns), you see that
x=y+3
Using that, the choices for the father's age are
41,52,63,74,85
But none of those works:
41+58=99
58+14=72
41-85=-44
52+47=99
47+25=72
52-74=-22
63+36=99
36+36=72
63-63=0
74+25=99
25+47=72
74-52=22
85+14=99
14+58=72
58-41=17
Maybe you can work it out...
So, if the father's age is xy and the son's age is ab, then we have
10x+y+10a+b=99
10a+b+10y+x=72
10x+y-(10b+a)=28
http://www.wolframalpha.com/input/?i=solve+10x%2By%2B10a%2Bb%3D99%2C+10a%2Bb%2B10y%2Bx%3D72%2C+10x%2By-%2810b%2Ba%29%3D28
If you look at the solution (undetermined, since we have only 3 equations and 4 unknowns), you see that
x=y+3
Using that, the choices for the father's age are
41,52,63,74,85
But none of those works:
41+58=99
58+14=72
41-85=-44
52+47=99
47+25=72
52-74=-22
63+36=99
36+36=72
63-63=0
74+25=99
25+47=72
74-52=22
85+14=99
14+58=72
58-41=17
Maybe you can work it out...
oops. 85-41=44
Still no joy.
Still no joy.