Question

answer the following question s

Answer 1

3. Assuming y to be the values of some data and x to be the frequency
 x         y             xy
4         2             4×2=8
6         4             6×4=24
7         p             7×p=7p
9         5             9×5=45

$mean = \frac{8+24+7p+45}{4+6+7+9} \\ \\ \Rightarrow 7= \frac{77+7p}{26} \\ \\ \Rightarrow 7 \times 26= 77+7p\\ \\ \Rightarrow 182-77=7p\\ \\ \Rightarrow 7p=105\\ \\ \Rightarrow p= \frac{105}{7}=\boxed{15}$

4. No, ΔABE and ΔACD are not congruent. The length of sides are not same. It is clear that AB≠AC. So they are not congruent.

Answer 2

mean =Σfixi /Σfi
       x/fi     y / xi     xy /fixi
       4         2             8
       6         4             24
       7         p             7p
       9         5             45
total:26      11+p        77+7p

mean =Σfixi /Σfi
   7      =77+7p/26
     cross multiplication
7x26=77+7p
182-77= 7p
105 =7p
105/7=p
15=p
p=15