Sol. Suppose the cost of one pen is Rs. X and the cost of one pencil is Rs. Y.
8x + 4y = 176 ………(i)
2x + 2y = 48 ………(ii)
On multiply by 2 in Eq. (ii), we get
4x + 4y = 96 ……….(iii)
On subtract Eq. (iii) from Eq. (i), we get
4x = 80
x = 20
So, the cost of one pen = Rs.20
Q7. The average marks in Science subject of a class of 20 students is 68. If the marks of two students were misread as 48 and 65 instead of the actual marks 72 and 61 respectively, what would be the correct average?
(a) Rs. 4000
(b) Rs. 4500
(c) Rs. 5000
(d) Rs. 4950
Q9. Three friends A,B and C begin to jog around a circular stadium and they complete their revolution in 54 seconds, 42 seconds, and 63 seconds respectively. After approximately how many minutes will they take to come together at the starting point?
(a) 6 min 18 sec
(b) 6 min 12 sec
(c) 5 min 45 sec
(d) 6 min
Q10. The angles of a quadrilateral are in the ratio of 2:4:7:5. The smallest angle of the quadrilateral is equal to the smallest angle of a triangle. One of the angle of the triangle is twice the smallest angle of the triangle. What is the second largest angle of the triangle?
Sol. Let angles of quadrilateral = 2x, 4x, 7x, and 5x
2x + 4x + 7x + 5x = 360°
Another angle of the triangle = 80°
Hence, desired second largest angle of the triangle = 180° -80° – 40° = 60°
Q11. Deepa rides her bike at an average speed of 30 kmph and reaches her destination in 6 hours. Hema covers the same distance in 4 hours. If Deepa increases her average speed by 10 kmph and Hema increases her average speed by 5 kmph, what would be the difference in their time taken to reach the destination?
will be as follows:
cm, Breadth = 46 + 4 = 50 cm
= 40 cm
surface = l × b + 2 × l × h + 2 × b × h
= 1.57 m2
painting 1.57 × 10 = Rs. 15.7