SOME USEFUL MATHS TRICKS

·         SOME USEFUL MATHS TRICKS

1.1/100=1%

2.1/9=11.111 or 11 1/9%

3.1/8=12.5%

4.1/7=14.28%

5.1/6=16.66666 or 16 2/3%

6.1/5=20%

7.1/4=25%

8.1/10=10%

9.1/16=6.25%

10.3/8=37.5%

11.5/8=62.5%

12.7/8=87.5%

13.1/16=6.25%

14.1/3=33.33 or 33 1/3%

15.2/3=66.66 or 66 2/3%

1.how to calculate a square of a no whose unit place has d digit 5 like 25*25 1st place 25 n den 2*3=6 plce 6 b4 25 answer is 625

2.1^2=1

2^2=4

3^2=9

4^2=16

diff of 1 n 4 is 3 4 n 9 is 5 16 n 9 is 7 everytime d diff is increasing by 2 nxt diff wl b 7+2=9 nw

add 9 to 16 which wl b 25 wich is 5^2

3. table 1

1^3=1

2^3=8

3^3=27

4^3=64

table 2

8-1=7

27-8=19

64-27=37

table 3

19-7=12

37-19=18

NW IN TABLE D DIFF OF DIFF IS INCREASING BY 6 SO NXT DIFF IN TABLE 3 WL 18+6=24 NW ADD DIS 2 LAST DIFF IN TABLE 2 37+24=61 NW 64+61=125 WHICH IS CUBE OF 5

4.HOW TO FIND AVERAGE OF N SET OF NOS WN 1 NO IS DIFF N (N-1) NOS ARE SAME LIKE FIND D AVERAGE OF 11,11,11,11 N 1 NORMAL WAY 2 DO IT =(11+11+11+11+1)/5=9 BT HERE V SHUD C D DIFF BETWEEN 11 N 1 WHICH IS 10 N DIVIDE IT BY NO OF TERMS WHICH IS 5 D RESULTING ANSWER WL B 10/5=2 NW SINCE 1 IS LESS THAN 11 AVERAGE WL B LESS THAN 11 WICH WL B 11-2=9 NW TAKE D OPP CASE LETS TK D AVERAGE OF 9,9,9 N 13 DIFF BETWN 13 N 9 IS 4 NW DIVIDE D DIFF BY D NOOF TERMS WICH IS 4 SO 4/4=1 SINCE 13 IS GREATER THAN 9 AVERAGE WL B GRTR DAN 9 WICH WL B 9+1=10 SO D FORMULA STANDS LIKE DIS

LET D DIFF BE D N NO OF TERMS B N a be the no wich is repetited and v d variable number so D=v-a(if v>a) or a-v(if a>v) k=d/n avg=a+k if v>a or a-k if a>v

5.Lets tk an eg of hw to find a square root of a perfect square m tkng 1681as an eg nw lets tk d frst two digits 16 its square root so square root of 1681 mst b in d 40's v knw 1*1=1 n 9*9=81so either d answer wl b either 41 or 49 bt here 1681is closer to 40's square d answer in all probability wl b 41

6. A total of 15000 rs is lent at si in two diff parts 1st at 10pc n d other at 7pc if at d end of 2yrs interest earned is rs 2400 wat r d two diff amt which wr lent nw hw to dishere total interest is 2400 fr 2 yrs so fr 1 yr its rs1200 p=15000 avg rate=1200*100/15000=8pc nw ratio of d sum lent wl b 8-7:10-8=1:2 nw divide 15000 in dis ratio which wl cm like dis 5000 at 10pc n 10000 at 7pc