In a network of railways, a small island has 15 stations. Find the number of different types of tickets to be printed for each class, if every stations must have tickets for other stations.

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is

On a railway there are 10 stations. The number of types of tickets required in order that it may be possible to book a passenger from every station to every other is

There are n stations on a railway line. The number of kinds of tickets printed (no return tickets) is 105. Find the number of stations

Hormones secreted by endocrine glands can have same or different types of action.find out the pair of hormones are not antagonistic (having opposite effects) to each other

A railway half ticket cost half the full fare but the reservation charges are the same on a half ticket as on a full ticket. One reserved first class ticket from the stations A to B costs Rs. 2530. Also, one reserved first class ticket and one reserved first class half ticket from stations A to B costs Rs. 3810. Find the full first class fare from stations A to B and also the reservation charges for a ticket.

A train going from station A to station B has 10 stations in between as halts. Nine persons enter the train duning the journey with nine different tickets of the same class. How many sorts of tickets they may have had.

Two types of tickets were sold for a concert held at an amphitheater. Tickets to sit on a bench during the concert cost $75 each, and tickets to sit on the lawn during the concert cost $40 each. Organizers of the concert announced that 350 tickets had been sold and that $19,250 had been raised through ticket sales alone. Which of the following systems of equations could be used to find the number of tickets for bench seats, B, and the number of tickets for lawn seats, L, that were sold for the concert?

Each of two parallel lines has a number of distinct points marked on them. On one line there are 2 points P and Q and on the other there are 8 points. i. Find the number of triangles formed having three of the 10 points as vertices. ii. How many of these triangles include P but exclude Q?

A bottle of red wine is thought to have been sealed about 5 years ago. The wine containa a number of different kinds of atoms, incluing carbon, oxygen,and hydrogen. Each of these has a radioactive isotope. The radiaoctive isotope of carbon is the familiar ._6^(14)C with a half-life of 5730 years . The radioactive isotope of oxygen is. ._(8)^(15)O and has a half-life of 122.2 s . The radioactive isotope of hydrogen ._1^(3)H and is called tritium, its half-life is 12.33 years . The activity of each of these isotopes is known at the time the bottle was sealed. However, only one of the isotopes is useful for determining the age of the wine accurately. Which is it?