math 一問

1.
$1000 is divided between Anna and Ben. If Ben receives less than twice as much as Anna by $200, how much does Anna receive?

Let
Anna receives $x
Ben receives $y

x + y = 1000……(Q1)
y = 2x - 200……(Q2)

put(Q2)into(Q1)
x + 2x - 200 = 1000
3x = 1200
x = 400

Therefore, Anna receives $400

2.
Pitt is 6 years old and his father is 46 years old now. After how many years will Pitt's age be 1/5 of his father's age?

Let x years needed

(6+x)/(46+x) = (1/5)
30+5x = 46+x
4x = 16
x= 4

Therefore, 4 years are needed

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1.$1000 is divided between Anna and Ben. If Ben receives less than twice as much as Anna by $200, how much does Anna receive?

Let x be the amount of money for Anna.

Anna's money = $ (x)
Ben's money = $ (2x - 200)

so,
Anna's money + Ben's money = the total

x + (2x - 200) = 1000
x + 2x - 200 = 1000
3x - 200 = 1000
3x = 1200
x = 400

So Anna gets $400. //



2.Pitt is 6 years old and his father is 46 years old now. After how many years will Pitt's age be 1/5 of his father's age?

Let y be the number of years.

6+y = 1/5 x (46 + y)
(6+y) x 5 = 1/5 x (4+y) x 5
30 + 5y = 46 + y
30 + 4y = 46
4y = 16
y = 4

It will take 4 years. //

Hope you find this useful :)