In a monthly test, the teacher decides that there will be three questions, one from each of the exercises IV, V and VI of the text book. If there are 10 questions in exercise IV, 15 in exercise V and 8 in exercise VI, find the number of ways in which three questions can be selected.

In a monthly test, the teacher decides that there will be three questions. one from each of Exercises 5, 6 and 7 of the text book. If there are 12 questions in Exercise 5, 18 in Exercise 6 and 9 in Exercise 7, in how many ways can the three questions be selected ?

There are p copies each of n different books. Find the number of ways in which a nonempty selection can be made from them.

In an examinations there are three multiple choice questions and each questions has 4 choices. Find the number of ways in which a student can fail to get all answer correct.

In an examination, Yamini has to select 4 questions from each part. There are 6, 7 and 8 questions in Part I, Part II and Part III respectively. What is the number of possible combinations in which she can choose the questions ?

In a multiple choice questions there are four alternative answers, of which one or more correct. A candidate will get marks in the question only if the ticks all the correct answers. The candidate decides to tick answers at random. If the is allowed upto three chances to answer the question, find the probability that he will get marks in the questions.

A mathematics paper consists of 10 questions divided into two parts I and II, each part containing 5 questions. A student is required to attempt 4 questions in all, taking at least 2 questions from each part. In how many ways can the student select the questions ?

A question paper consists of two sections having respectively 3 and 4 questions. The following note is given on the question paper : "It is not necessary to attempt all the questions. One question from each part is compulsory.”’ In how many ways Can a candidate select the questions ?

A question paper consists of two sections having respectively, 3 and 5 questions. The followinng note is given on the paper "it is not necessory to attempt all the questions one questions from each section is compulsory". In how many ways can candidate select the questions?

These questions consist of two statements each,printed as Assertion and Reason.While answering these questions you are required to chose any one of the following four responses. If both Assertion and Reason are true and Reason in correct explanation of Assertion. If both assertion and Reason are true but reason is not correct explanation of Assertion. If Assertion is true but Reason is false. If both Assertion and Reason are false. Assertion:During exercise , a person undergoes fatigue very soon. Reason:During this period ,muscle fibres undergo oxygen debt.

• Take three iron nails and clean them by rubbing with sand paper. • Take two test tubes marked as (A) and (B). In each test | tube, take about 10 ml copper sulphate solution. • Tie two iron nails with a thread and immerse them 'carefully in the copper sulphate solution in test tube B for about 20 minutes [Fig. (a)]. Keep one iron nail aside for comparison. • After 20 minutes, take out the iron nails from the copper sulphate solution. • Compare the intensity of the blue colour of copper sulphate solutions in test tubes (A) and (B) (Fig. (b)]. Also, compare the colour of the iron nails dipped in the copper sulphate solution with the one kept aside [Fig. - (b)]. On the basis of activity , give the answers of th following questions : What is the colour of copper sulphat solution in test tube A ?