algebra

Mary is 24 years old. Mary is twice as old as Ann was when Mary was as old as Ann is now. How old is Ann now?

The sum of Kim's and Kevin's ages is \(18\). In \(3\) years, Kim will be twice as old as Kevin. What are their ages now?

Robert is \(15\) years older than his brother Stan. However "y" years ago, Robert was twice as old as Stan. If Stan is now "b" years old and \(b>y\), find the value of \((b - y)\).

JJ is three times as old as Jan-Jan. Three years ago, JJ was four times as old as Jan-Jan. The sum of their ages is

A girl is one-third as old as her brother and \(8\) years younger than her sister. The sum of their ages is \(38\) years. How old is the girl?

Paula is now \(18\) years old and his colleague Monica is \(14\) years old. How many years ago was Paula twice as old as Monica?

A father tells his son, "I was your age now when you were born." If the father is now \(38\) years old, how old was his son \(2\) years ago?

Six years ago, Nilda was five times as old as Riza. In five years, Nilda will be three times as old as Riza. What is the present age of Riza?

At present, the sum of the parents' ages is twice the sum of the children's ages. Five years ago, the sum of the parents' ages was \(4\) times the sum of the children's ages. Fifteen years hence, the sum of the parents' ages will be equal to the sum of the children's ages. How many children are there?

Debbie is now twice as old as Jerry. Four years ago, Debbie was three times as old as Jerry then. How old is Debbie?

A pump can pump out water from a tank in \(11\) hours. Another pump can pump out water from the same tank in \(20\) hours. How long will it take both pumps to pump out the water in the tank?

A \(400\)-mm \(\emptyset\) pipe can fill the tank alone in \(5\) hours and another \(600\)-mm \(\emptyset\) pipe can fill the tank alone in \(4\) hours. A drain pipe \(300\)-mm \(\emptyset\) can empty the tank in \(20\) hours. With all the three pipes open, how long will it take to fill the tank?

A tank is filled with an intake pipe in \(2\) hours and emptied by an outlet pipe in \(4\) hours. If both pipes are opened, how long will it take to fill the empty tank?

A tank can be filled in \(9\) hours by one pipe, \(12\) hours by a second pipe and can be drained when full by a third pipe in \(15\) hours. How long will it take to fill an empty tank with all pipes in operation?

If A can do the work in "\(x\)" days and B in "\(y\)" days, how long will they finish the job working together?

Pedro can paint a fence \(50\%\) faster than Juan and \(20\%\) faster than Pilar, and together they can paint a given fence in \(4\) hours. How long will it take Pedro to paint the same fence if he had to work alone?

Glenn can paint a house in \(9\) hours while Stewart can paint the same house in \(16\) hours. They work together for \(4\) hours. After \(4\) hours, Stewart left and Glenn finished the job alone. How many more days did it take Glenn to finish the job?

It takes Butch twice as long as it takes Dan to do a certain piece of work. Working together they can do the work in \(6\) days. How long would it take Dan to do it alone?

A and B working together can finish painting a house in \(6\) days. A working alone can finish it in \(5\) days less than B. How long will it take each of them to finish the work alone?

A and B can do a piece of work in \(42\) days, B and C in \(31\) days and C and A in \(20\) days. In how many days can all of them do the work together?