In a survey of 100 students, the number of students studying the various languages is found as English only 18; English but not Hindi 23; English and Sanskrit 8; Sanskrit and Hindi 8; English 26; Sanskrit 48 and no language 24. Find
(i) how many students are studying Hindi?
(ii) how many students are studying English and Hindi both?
Given:
- Total number of students $=100$
- Number of students studying English(E) only $=18$
- Number of students learning English but not Hindi(H) $=23$
- Number of students learning English and Sanskrit(S) $=8$
- Number of students learning Sanskrit and Hindi = 8
- Number of students learning English = 26
- Number of students learning Sanskrit = 48
- Number of students learning no language $=24$
To Find:
(i) Number of students studying Hindi
Venn diagram:
From the above Venn diagram
$\mathrm{a}=$ Number of students who study only English $=18$
$\mathrm{~b}=$ Number of students who study only Sanskrit
$\mathrm{c}=$ Number of students who study only Hindi
$\mathrm{d}=$ Number of students learning Hindi and Sanskrit but not English
$\mathrm{e}=$ Number of students learning English and Sanskrit but not Hindi
$\mathrm{f}=$ Number of students learning Hindi and English but not Sanskrit
$\mathrm{g}=$ Number of students learning all the three languages
$\mathrm{e}+\mathrm{g}=$ Number of students learning English and Sanskrit $=8$
$=n(E \cap S)$
g + d = Number of students learning Hindi and Sanskrit = 8
$=n(H \cap S)$
$E=a+e+f+g=$ Number of students learning English $26=18+8+f$
$f=26-26=0$
Therefore, $f=0$
Now
Number of students learning English but not Hindi = a + e = 23
$23=18+e$
Therefore, $e=5$
Now, $e+g=8$
$5+g=8$
Therefore, $g=3$
$S=b+e+d+g=$ Number of students studying Sanskrit
$48=b+5+8$ (Because, $d+g=8$ )
$b=48-13$
Therefore, $b=35$ (Number of students studying Sanskrit only)
Also, $d+g=8$
$d+3=8$
Therefore, $d=5$
Now,
Number of students studying Hindi only $=c$
$c=100-(a+e+b+d+f+g)-24$
$=100-(18+5+35+5+0+3)-24$
$=100-66-24$
$=100-90=10$
Number of students studying Hindi $=c+f+g+d$
$=10+0+3+5$
$=18$
Therefore, number of students studying Hindi $=18$
(ii) Number of students studying English and Hindi both
Number of students studying English and Hindi both $=f+g$
$=0+3=3$
Therefore, Number of students studying English and Hindi both = 3