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Answer:
30 students
Step-by-step explanation:
3 students = 10% of the class.
x students = 90% of the class.
(If more, less divides. Let x be the subject. Since we know 10% of the class already, we have to find the remaining 90% that is 100% - 10% = 90%.)
x = 90%/ 10% × 3 students. ( the percentage signs cancel out and so do the zero's.)
x= 9/1 × 3 students ( 9/1 is the same as 9)
x= 27 students
(To find the total, you must add the 10% of the students to the remaining 90% of the students in the class.)
Total number of students in the class = 27 students + 3 students
= 30 students
Answer:
17/12 = 1 5/12
Step-by-step explanation:
The common denominator of 4 and 3 is 12.
The equivalent fraction of 3/4 is 9/12.
The equivalent fraction of 2/3 is 8/12.
Their total is 17/12 (or 1 5/12).
Answer:
Option A is correct, i.e. x = -3, x = 7.
Step-by-step explanation:
Given the equation is x² -4x -21 = 0.
We can compare it with general quadratic equation i.e. ax² +bx +c =0.
then a = 1, b = -4, c = -21.
We can use Quadratic formula as follows:-
x = ( -b ± √(b²-4ac) )/2a
x = ( +4 ± √(16-4*1*-21) )/2*1
x = ( +4 ± √(16+84) )/2
x = ( +4 ± √(100) )/2
x = ( +4 ± 10 )/2
x = (4+10)/2 or x = (4-10)/2
x = 14/2 or x = -6/2
x = 7 or x = -3
Hence, option A is correct, i.e. x = -3, x = 7.
