m = the amount she had originally
She spent:
1 / 8 of her money = m / 8 to buy books
1 / 5 of her money = m / 5 in purchasing clothes
and
1 / 10 of her money = m / 10 in purchasing clothes
She spent total: m / 8 + m / 5 + m / 10
Rest of money = m - ( m / 8 + m / 5 + m / 10 ) = m - m / 8 - m / 5 - m / 10
She still had Rs 15, more than half of her money mean:
Rest of money = m / 2 + 15
So:
m / 2 + 15 = m - m / 8 - m / 5 - m / 10
20 ∙ m / 20 ∙ 2 + 40 ∙ 15 / 40 = 40 m / 40 - 5 ∙ m / 5 ∙ 8 - 8 ∙ m / 8 ∙ 5 - 4 ∙ m / 4 ∙ 10
20 m / 40 + 600 / 40 = 40 m / 40 - 5 m / 40 - 8 m / 40 - 4 m / 40
( 20 m + 600 ) / 40 = ( 40 m - 5 m - 8 m - 4 m ) / 40
( 20 m + 600 ) / 40 = 23 m / 40
Multiply both sides by 40
20 m + 600 = 23 m
Subtract 20 m to both sides
20 m + 600 - 20 = 23 m - 20 m
600 = 3 m
3 m = 600
Divide both sides by 3
m = 600 / 3
m = 200 Rs
Proof:
She spent:
1 / 8 of her money = 200 / 8 = 25 Rs to buy books
1 / 5 of her money = 200 / 5 = 40 Rs in purchasing clothes
and
1 / 10 of her money = 200 / 10 = 20 Rs in purchasing clothes
She spent total: 25 + 40 + 20 = 85 Rs
Rest of money = 200 - 85 = 115 Rs = ( 100 + 15 ) Rs = ( 200 / 2 + 15 ) Rs
Samina spent 1/8 of her money to buy books, 1/5 in purchasing clothes and 1/10 on charity. If she still had Rs 15, more than half of her money, find the amount she had originally.
2 answers
One my typo:
not
Subtract 20 m to both sides
20 m + 600 - 20 = 23 m - 20 m4
than
Subtract 20 m to both sides
20 m + 600 - 20 m = 23 m - 20 m
not
Subtract 20 m to both sides
20 m + 600 - 20 = 23 m - 20 m4
than
Subtract 20 m to both sides
20 m + 600 - 20 m = 23 m - 20 m