Find the mean of the following distribution :
Class 30 – 40 40 – 50 50 – 60 60 – 70 70 – 80
Frequency 6 13 8 12 11
calculate class mark, mid value or mid -x [x] then the product f*x
Class f x f*x
30-40 6 35 210
40-50 13 45 585
50-60 8 55 440
60-70 12 65 780
70-80 11 75 825
Total Σf =50, Σfx= 2840
Mean = Σfx / Σf = 2840 / 50 = 56.8
for more explanation watch this video
statistics arithmetic mean by direct method
cbse 10th maths previous years question papers 2025 2026 question in statistics
Real Numbers H.C.F, LCM ... (part 1)
link for real numbers HCF LCM ...(Part 2)
A milk man has 175 litres of cow’s milk and 105 litres of buffalo’s milk. He wishes to sell the milk by filling the two types of milk in cans of equal capacity. Calculate the following (i) Capacity of a can (ii) Number of cans of cow’s milk (iii) Number of cans of buffalo's milk
solution video2.National Art convention got registrations from students from all parts of the country, of
which 60 are interested in music, 84 are interested in dance and 108 students are interestedin handicrafts. For optimum cultural exchange, organisers wish to keep them in minimum
number of groups such that each group consists of students interested in the same artform
and the number of students in each group is the same. Find the number of students in each
group. Find the number of groups in each art form. How many rooms are required if each
group will be allotted a room?
solution
3.Find by prime factorisation the L.C.M. of the numbers 18180 and 7575. Also find the HCF of the two numbers
4. Find the smallest number which is divisible by 8, 9 and 10
