A student gets 4 marks for each correct answer and 1 mark is deducted for a wrong answer. If he had done 80 questions at all and he has got only 240 marks, The correct answer he has attempted are?
Suppose he has done x questions correctly.
Then it means he has done (80-x) questions wrong.
So, 4 (x) â€“ 1 (80 -x ) =240
5x â€“ 80 = 240
5x = 320
X = 64
In a bag there are 10 red and 15 blue marbles. Two marbles are drawn in succession without replacement. What is the probability that first is red and second is blue
Probability that first one is red = 10/25 = 2/5
Probability that second one is blue = 15/24 = 5/8
probability that first is red and second is blue = 2/5 * 5/8 = 1/4
Let the speed of the current = 'x' km/hr
Speed of motor boat = 25/3 m/s = (25/3)*18/5 = 30 KM/hr
We have 75/(30+x) + 75/(30-x) = 9
â‡’ 75(60/(900-x2)) = 9
â‡’ 900-x2 = 500
â‡’ x2 = 400
â‡’ x = 20km/hr
Marks of Lokesh = 98 %
so that of Avinash will be 98-1 = 97%
now we have to find the % of difference of marks w. r. t. marks of Avinash it will be
1*100/97 = 100/97 = 1.031
How many ways are possible to arrange 4 boys and 3 girls for a dinner, if there are two straight benches of capacity 5 and 2 persons for their sitting?
Total no. of persons = 7
Since benches are straight, therefore arranging them in benches of capacity 5 and 2 persons is
equivalent to arranging them in a straight bench of capacity 7 persons.
Total no. of methods
= 7*6*5*4*3*2*1 = 5040
A student got 68 % in the board examination. What would be his percentage, if he got 10 % (of the total marks of the subject) more marks in physics, chemistry and mathematics? Total marks are 500 and every paper is of 100 marks.