SOLUTION: 1st question) marks dad is 3 times as old as mark . The sum of their ages is 48 , how old is mark? most importantly i need the expression (: thankyouu 2nd question. ) bilal

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Question 536204: 1st question) marks dad is 3 times as old as mark . The sum of their ages is 48 , how old is mark?
most importantly i need the expression (: thankyouu
2nd question. )
bilal sister is 3 years younger than bilal , bilal's mother is 3 times than bilal's age , bilal's father is 4 years old then bilal's mother , the sum of all ages is 89 , how old was bilal's mother when he was born?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = Dad's age
Let +m+ = Mark's age
given:
(1) +d+%2B+m+=+48+
(2) +d+=+3m+
---------
Substitute (2) into (1)
(1) +3m+%2B+m+=+48+
(1) +4m+=+48+
(1) +m+=+12+
and,
(2) +d+=+3m+
(2) +d+=+36+
Dad is 36 and Mark is 12
--------------------
Let b = Bilal's age now
Let s = Bilal's Sister's age now
Let m = Mother's age now
Let f = Father's age now
given:
(1) +b+%2B+m+%2B+f+=+89+
+s+=+b+-+3+
(2) +m+=+3b+
(3) +f+=+m+%2B+4+
How old was bilal's mother when he was born?
This is the same as " What is +m+-+b+ ?"
(2) +m+=+3b+
+m+-+b+=+3b+-+b+
+m+-+b+=+2b+
and
(1) +b+%2B+m+%2B+m+%2B+4+=+89+
(1) +b+%2B+3b+%2B+3b+%2B+4+=+89+
(1) +7b+=+85+
(1) +b+=+85%2F7+
+m+-+b+=+2b+
+m+-+b+=+170%2F7+
+m+-+b+=+24.286+
+.286%2A12+=+3.428+
His mother was 24 and 3 months old
Hope I got it