Class 10 Term 2 Standard Maths Solution [Series- PPQQA/1 Set 1, Paper Code- 30/1/1]
SECTION A
Question 1- Find the sum of first 30 terms of AP: -30, 24, -18,/..
Solution- a= -30, d= 6
= 15 [-60 + 29 (6)]
= 15 [-60+174]
= 15 [114]
= 1710
ORQuestion 1- If an AP is Sn = n(4n+1), then find the AP
Solution- S1 = T1 = 5
S2= T1 + T2= 18
S2-S1 = T2= 13
AP= 5, 13, 21, 29, …
Question 2- A solid metallic sphere of radius 10.5 cm is melted and recast into a number of smaller cones, each of radius 3.5 cm and height 3 cm. Find the number of cones so formed.
Solution- r1 = 10.5 cm (sphere) and r2 (cone)= 3.5 cm, h2= 3cm
4/3πr³ = n x 1/3πr2² h
4r³ = nr2² h
4 x (105/10)³= n x 35/10 x 35/10 x 3
21 x 6= n
Number of cones formed= 126
Question 3 (a) Find the value of m for which the quadratic equation
(m-1) x² + 2(m-1)x + 1 = 0
Solution- D= 0
4 (m-1)² - 4(m-1) = 0
4 (m-1) [m-1-1]= 0
(m-1) (m-2)= 0
m= 2
(b) Solve the following quadratic equation for x: √3x² + 10x + 7√3= 0
Solution- √3x² + 3x + 7x + 7√3= 0
√3x (x+ √3) + 7 (x + √3)= 0
(x+ √3) [√3x + 7]= 0
x= √3 || x= -7/√3
Question 4- Find the mode of the following frequency distribution:
| Class | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Frequency | 15 | 10 | 12 | 17 | 4 |
Solution- l= 40, f1= 17, f2= 4, fo= 12
Mode= l + f1-fo / 2f1 - fo- f2
= 40 + 17-12 / 34-12-4 x 10
= 40 + 5/18 x 10
= 40 + 25/9
= 40 + 2.78
= 42.78
Question 5- The product of Rehan's age (in years) 5 years ago and his age 7 years from now, is one more than twice his present age. Find his present age.
Solution
| Past Age | Present Age | Future Age |
| x-5 | x | x+7 |
(x-5) (x+7) = 2x + 1
x² + 2x -35 = 2x+1
x² - 36 = 0
x² = 36
x= +_ 6
Present Age- 6 years
Question 6 Two concentric circles are of radii 4 cm and 3 cm. Find the length of the chord of the larger circle which touches the smaller circle.
Solution-
SECTION B
Question 7- For what value of x, is the median of the following frequency distribution 34:5?
| Class | Frequency |
| 0-10 | 3 |
| 10-20 | 5 |
| 20-30 | 11 |
| 30-40 | 10 |
| 40-50 | x |
| 50-60 | 3 |
| 60-70 | 2 |
Question 8- Draw a circle of radius 3 cm. Take two points P and Q on one of its extended diameter each at a distance of 7 cm from its centre. Construct tangents to the circle from these two points P and Q.
Question 9-(a) The angle of elevation of the top of a building from the foot of the tower is 30° and the angle of elevation of the top of the tower from the foot of the building is 60°. If the tower is 50 m high, then find the height of the building.
tan 60° = 50/b
Question 10- Following is the daily expenditure on lunch by 30 employees of a company, Find the mean daily expenditure of the employees.
Question 11- From a solid cylinder of the height of 30 cm and radius of 7 cm, a conical cavity of height of 24 cm and same radius is hollowed out. Find the total surface area of the remaining solid.
(a) Write the AP for the number of triangles used in the figures. Also, write the nth term of this AP. Which figure has 61 matchsticks?