7th Class
Mathematics
Related to Competitive Exam
Question Bank
Mathematical Operations
question_answer
DIRECTIONS: In each of the following questions, three statements of numbers following same rules are given. Find the rule and accordingly find the value of the number? If 7*3 = 52; 9*5 = 86; 3*4 = 13, then 5*7 =?
A)30
B)32
C)40
D)57
E)42
Correct Answer:
B
Solution :
The rule is: \[a*b={{a}^{2}}+b\] \[7*3=49+3=52\,\text{etc}\text{.}\] \[\therefore \] \[5*7=25+7=32\]