algebra

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?

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?

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 \(400\)-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 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?

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?

It takes Myline twice as long as Jeana to do a certain piece of work. Working together, they can finish the work in \(6\) hours. How long would it take Jeana to do it alone?

A farmer can plow the field in \(8\) days. After working for \(3\) days, his son joins him and together they plow the field in \(3\) more days. How many days will it require for the son to plow the field alone?

Ten liters of \(25\%\) salt solution and \(15\) liters of \(35\%\) salt solution are poured into a drum originally containing \(30\) liters of \(10\%\) salt solution. What is the per cent concentration of salt in the mixture?

A Chemist of a distillery experimented on two alcohol solutions of different strength, \(35\%\) alcohol and \(50\%\) alcohol, respectively. How many cubic meters of each strength must he use in order to produce a mixture of \(60\) cubic meters that contain \(40\%\) alcohol?

A goldsmith has two alloys of gold, the first being \(70\%\) pure and the second being \(60\%\) pure. How many ounces of the \(60\%\) pure gold must be used to make \(100\) ounces of an alloy which will be \(66\%\) gold?

Two thousand (\(2000\)) kg of steel containing \(8\%\) nickel is to be made by mixing a steel containing \(14\%\) nickel with another containing \(6\%\) nickel. How much of each is needed?

How much water must be evaporated from \(10\) kg solution which has \(4\%\) salt to make a solution of \(10\%\) salt?

Find the fraction such that if \(2\) is subtracted from its terms its becomes \(1/4\), but if \(4\) is added to its terms it becomes \(1/2\).

The product of \(\frac{1}{4}\) and \(\frac{1}{5}\) of a number is \(500\). What is the number?