72% of 25 students are good in mathematics. How many are not good in mathematics?

There are 102 students in a class. In an examination, 50 of them failed in Mathematics, 45 failed in Physics and 40 failed in Chemistry, 32 failed in exactly two of these three subjects. Only one student passed in all the three subjects. Find the number of students failing in all the three subjects.

20 students are getting 'letter marks' either in Mathematics or in Advanced Mathematics. If 12 of them get letter marks in Mathematics and 9 of them in both, how many of them get letter marks in Adv. Mathematics.

In a class 18 students offered Physics, 23 offered Chemistry and 24 offered Mathematics. Of them, 13 offered both Chemistry and Mathematics, 12 offered both Physics and Chemistry, 11 offered both Mathematics and Physics and 6 offered all three. Find the number of students in the class.

Some students arranged a picnic.The budget of food was ₹2400.Four students of the gourp failed to go.The cost of food for each student got increased by ₹50.How many students went for the picnic?

Among the number of students in a class 25 read physics.30 read chemistry and 20 read mathematics.If 12 read both physics and chemistry,15 read chemistry and mathematics,18 read physics and mathematics and 10 read all the three subjects find the number of students in the class.

There are 60 students in a class. Out of them 25 students play foot ball and 20 students play cricket and 10 of them play both , how many of them play neither are.

Among a group of 90 students,40 like mathematics and 60 like chemistry.If 6 students like neither,find how many like both the subjects?

Form the pair of linear equations in the following problems,and find their solution graphically.(i)10 students of class X took part in a Mathematics quiz.If the number of girls is 4 more than the number of boys,find the number of boys and girls who took part in the quiz.

Out of 45 students, 22 of them can speak only Hindi and 11 of them can speak both English and Hindi. How many of them can speak only English ?

How would you account for the following? The transition metal compounds are good catalyst.