Bobby and his younger brother Johnny have the same birthday. Johnny's age now is the same as Bobby's age was when Johnny was half as old as Bobby is now. What is Bobby's age now?
(1) Bobby is currently four times as old as he was when Johnny was born.
(2) Bobby was six years old when Johnny was born.
Please help convert the sentences in equations.
An English Language Test Rather Than Maths Test
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- ronnie1985
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Let Johnny's present age be x and Bobby's present age be y.ronnie1985 wrote:Bobby and his younger brother Johnny have the same birthday. Johnny's age now is the same as Bobby's age was when Johnny was half as old as Bobby is now. What is Bobby's age now?
(1) Bobby is currently four times as old as he was when Johnny was born.
(2) Bobby was six years old when Johnny was born.
Please help convert the sentences in equations.
Half of Bobby's age is y/2.
Johnny must have been y/2 years of age (x-y/2) years ago.
At that time Bobby must have been y - (x - y/2) = 3y/2 - x years of age.
So x = 3y/2 - x
2x = 3y/2
4x = 3y
(1) Bobby is currently four times as old as he was when Johnny was born.
When Johnny was born, Bobby must have been y - x years of age.
4*(y - x) = y
3y = 4x
This is just the same equation as what we get from the main question; NOT sufficient.
(2) Bobby was six years old when Johnny was born implies y - x = 6.
So we have 2 equations, 4x = 3y and y - x = 6.
x = 18 and y is 24.
So Bobby's age now is 24 years; SUFFICIENT.
The correct answer is B.
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Johnny's age now is the same as Bobby's age was when Johnny was half as old as Bobby is now.
This sentence was indeed difficult to identify, could you make it more easier to understand please...
Because of that I am not able to make the equation...
This sentence was indeed difficult to identify, could you make it more easier to understand please...
Because of that I am not able to make the equation...
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Johnny's age now is the same as Bobby's age was when Johnny was half as old as Bobby is now;[email protected] wrote:Johnny's age now is the same as Bobby's age was when Johnny was half as old as Bobby is now.
This sentence was indeed difficult to identify, could you make it more easier to understand please...
Because of that I am not able to make the equation...
IMO we can start with relative clause first:
MAIN CLAUSE: Johnny's age now is the same as Bobby's age was (B1) WHEN XX
RELATIVE CLAUSE 'XX' = Johnny was half as old as Bobby is now (B) ==> Johnny was half as old as B ==> XX = (B/2)
Bobby's age (B1) was WHEN JONNEY WAS B/2==> B1 = B-(J-B/2)=3B/2-J
Lets go to main clause: Johnny's age now is the same as B1 = Johnny's age now is the same as 3B/2-J ==> J = 3B/2-J
IMO we need to start from END TO START