Question

In a row of students facing north, B is 18th from the left and third to the right of D, who is 15th from the right end. How many students are there in the row? a) 30 b) 20 c) 33 d) 29 e) None of these

Answer 1

Answer:

d) 29

B is 18th from left and third to D

so D will be 18-3 =15th from left

also as given D is 15th from right

so D is the middle

so 14 students stand in the left of D

and 14 in the right of him

so

total students =14+14+1

=29

Answer 2

${\texttt{\blue{Refers\: to \: the \: Attachment}}}$

${\boxed{\mathtt{\green{Solution\:⇢}}}}$

➾ B is at 18th position from left

➾ There are 2 persons between B and D .

➾ Let's assume those 2 people as x and y .

So position of x and y from left will be :-

$x \: = \: \boxed{16th \: position}$

$y \: = \: \boxed{17th \: position}$

D is just left to y . So the position of D will be

$D \: = \: \boxed{ \: 15st \: position}$

➾ Behind D there are 14 persons in the row .

$\implies \: { \boxed {\red{15 \: persons \: + \: 14 \: persons \: = total}}}$

$\implies \: { \boxed{ \mathtt{ \red{ total \: persons \: = \: 29}}}}$

If We solve from other side then :-

$y\: = \: \boxed{13th \: position}$

$x \: = \: \boxed{14th \: position}$

D is 15th person and x is 14th

$\implies \: {\boxed{ \red{15 + 14}}}$

$\implies \: { \boxed{ \mathtt {\red{ total \: persons \: = 29}}}}$

Answer is d option.