find the missing number?
8,15,36,99,?,855
a)274
b)288
c)264
d)none of these

• 15-8=7
  36-15=21
  99-36=63
  ?-99=189 [As,Difference are 7,7*3=21,21*3=66,66*3=189,189*3=567....]
  so missing term is (99+189=288)
  Ans:b)288
• 10 years agoHelpfull: Yes(16) No(2)
• 8=8
  15=1+5=6
  36=3+6=9
  99=9+9=18=1+8=9
  855=8+5+5=18=1+8=9
  As we see these are the differences that we need to subtract. Hence the following numbers are subtracted.
  8*1+7=15
  15*2+6=36
  36*3-9=99
  99*3-9=288
  288*3-9=855
• 10 years agoHelpfull: Yes(4) No(2)
• 15-8, 36-15, 99-36, ?-99, 855-?
  
  => 7, 21, 63, ...
  => 7*1, 7*3, 7*9, next should be 7*27 i.e. 189
  
  so the missing number is 99+189 = 288
• 10 years agoHelpfull: Yes(3) No(0)
• 8*3-9=15
  15*3-9=36
  36*3-9=99
  99*3-9=288
  288*3-9=855
• 8 years agoHelpfull: Yes(2) No(0)
• 15-8=7x1
  36-15=21=7x3
  99-36=63=7x9
  similarly
  x-99=7x27=189 ==> x=288
• 10 years agoHelpfull: Yes(1) No(0)
• 288
  diffence there is 7,21,63, than 189 nd 567
• 10 years agoHelpfull: Yes(0) No(1)
• difference between first two number is 7 then next 2 nos diff is 21(3 times of 7)thn 63(3 times of 21) so the next difference should be 189,the final value is 99+189=288
• 10 years agoHelpfull: Yes(0) No(1)
• 288
  
  differences....7,21,63,189,567
• 9 years agoHelpfull: Yes(0) No(1)
• The common difference is 7,21,63,189 so on...that means its in GP with common ratio 3.. hence 4th number will be 99+189 = 288
• 8 years agoHelpfull: Yes(0) No(1)
• 15-8=7
  36-15=21; 7*3=21
  99-36=63; 21*3=63
  according through above procedure we can write
  63*3=189+99=288
• 8 years agoHelpfull: Yes(0) No(1)
• b)288
  explanation:-
  difference between numbers is 7,21,63,.....
• 8 years agoHelpfull: Yes(0) No(1)
• 288. 15-8=7,36-15=21,99-36=63 ie.....7,7*3=21,21*3=63,63*3=189
  99+189=288.
• 7 years agoHelpfull: Yes(0) No(0)
• 15-8=7
  36-15=21
  99-36=63
  ?-99=189 [As,Difference are 7,7*3=21,21*3=63,63*3=189,189*3=567....]
  so missing term is (99+189=288)
• 7 years agoHelpfull: Yes(0) No(0)
• answer is 288
  every term is increasing by 3rd multiple of 7,21,63,189,567.
• 7 years agoHelpfull: Yes(0) No(0)
• answer is 288
  
  
  First we have to find the difference of the given number.
  
  15 - 8 = 7.
  36 - 15 = 21.
  99 - 36 = 63.
  
  The difference number is like;
  7 * 3 = 21
  21 * 3 = 63
  63 * 3 = 189.
  189 * 3 = 567
  
  We have to find the next number of 99.
  So, 99 + 189 = 288
  => 288 + 567 = 855.
• 6 years agoHelpfull: Yes(0) No(0)
• Ans Wii be 288
  B'coz 15-8=7
  36-15=21
  99-36=63
  288-99=189
  855-288=567
  Off course completely difference multiple of 3 itself
• 6 years agoHelpfull: Yes(0) No(0)
• the missing no. is 288
  8,15,36,99
  7,21,63 are the first difference and we can see that each no. is a multiplication of 3 and the previous no. so the next no. after 63 will be 63*3=189
  therefore 99+189 = 288
• 6 years agoHelpfull: Yes(0) No(0)
• 8+7=15
  15+21(i.e,7*3)=36
  36+63(i.e,21*3)=99
  similarly,
  99+199(63*3)=288
• 4 years agoHelpfull: Yes(0) No(0)