5 11 6 9
13 18 11 20
21 25 16 ?
Check your answer:-
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Answer is 31.
How?
Look at columns, difference between second column number to first column number is same as difference between third column number and second column number, i.e.
How?
Look at columns, difference between second column number to first column number is same as difference between third column number and second column number, i.e.
c[i+1] – c[i] = c[i+2] – c[i]
lets assume missing number is X, thus
20 – 9 = X – 20
X = 40 -9 = 31
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31
first row – 5+11+6+9=31
second row – 13+18+11+20=62
third row – 21+25+16+”31″=93
all the row difference 31
ans is 31 when you read the columns up to down
5 (+6) 11 descending order (-1) 6 (+3) 9
13 (+5) 18 11(+9) 20
21 (+4)25 16 ?(+8)=24
24
31
3rd row, how come 5? please check again.
Look at the columns, not the rows for the answer, silly.
31
31
so ans is 31
31 in 1st row 5+8= 13, 13+8=21 2nd row 7 is added,3rd row 5 is added so here 11 is added so 9+11=20, 20+ 11=31