81) a box consists of 100 shirts of which 88 are good, 8 have minor defects and 4 have major defects. ramesh, a shopkeeper will buy only those shirts which are good but ‘kewal’ another shopkeeper will not buy shirts with major defects. a shirt is taken out of the box at random. what is the probability that
i) ramesh will buy the selected shirt ?
ii)‘kewal’ will buy the selected shirt ?

Watch this and practise to learn english tenses with the easiest method you will ever know. just use your hands and fingers to remember the names and functions of tenses! all the best!

79) two different dice are thrown together. find the probability of :
getting a number greater than 3 on each die
getting a total of 6 or 7 of the numbers on two dice

76) the angles of depression of the top and bottom of a 50m high building from the top of a tower are 45° and 60° respectively. find the height of the tower and the horizontal distance between the tower and the building (use √3 = 1.73)

75) the sum of the radius of base and height of a solid right circular cylinder is 37cm. if the total surface area of the solid cylinder is 1628 sq. cm, find the volume of the cylinder. (use π = 22/7)

74) a well of diameter 4m is dug 21m deep. the earth taken out of it has been spread evenly all around it in the shape of a circular ring of width 3m to form an embankment. find the height of the embankment.

71) in fig. , are shown two arcs paq and pbq. arc paq is a part of circle with centre o and radius op while arc pbq is a semi-circle drawn on pq as diameter with centre m. if op = pq = 10 cm show that area of shaded region is 25 (√3 - "π" /6) cm2

70) in fig., abc is a triangle, coordinates of whose vertex a are (0, – 1). d and e respectively are the mid-points of the sides ab and ac and their coordinates are (1, 0) and (0, 1) respectively. if f is the mid-point of bc, find the areas of Δabc and Δdef.

In fig., is a decorative block, made up of two solids – a cube and a hemisphere. the base of the block is a cube of side 6 cm and the hemisphere fixed on the top has a diameter of 3.5 cm. find the total surface area of the block. (use π = 22/7)
explained by: brijesh sharma