If each pupil in a class sends a New Year greeting card to every classmate, the total number of cards sent out will be 870. Find the number of pupils in the class.
Answers
#If a class would have 2 students then the number of cards would be 2.
#Now if the class would have 3 students then the number of cards would be 6. (1 student will give it to the other 2 students. Like this 3 times.)
#From the above examples we can generalize the logic.
As the total cards are 870,
We get,
x(x-1)=870
On solving we get
x=30.
Therefore the no. of students in the class is 30.
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Answer:
Correct option is
B
p=7/3,q=0
Suppose Points P and Q trisect the line segment joining the pointsA(3,−4) and B(1,2)
This means, P divides AB in the ratio 1:2 and Q divides it in the ratio 2:1
Using the section formula, if point (x,y) divides the line joining the points (x
1
,y
1
) and (x
2
,y
2
) internally in the ratio m:n, then(x,y)=(
m+n
mx
2
+nx
1
,
m+n
my
2
+ny
1
)
Substituting (x
1
,y
1
)=(3,−4) and (x
2
,y
2
)=(1,2) and m=1,n=2 in the section formula, we get the point P =(
1+2
1(1)+2(3)
,
1+2
1(2)+2(−4)
)=(
3
7
,−2)
Given. P(p,−2)=(
3
7
,−2)
=>p=
3
7
Substituting (x
1
,y
1
)=(3,−4) and (x
2
,y
2
)=(1,2) and m=2,n=1 in the section formula, we get the point Q =(
2+1
2(1)+1(3)
,
2+1
2(2)+1(−4)
)=(
3
5
,0)
Given. Q(
3
5
,0)=(
3
5
,q)
=>q=0
Step-by-step explanation:
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