When x + y + z = 9 and xy + yz + zx = 11, then x3 - y3 - z3 - 3xyz equals
A. | 384 |
B. | 192 |
C. | 432 |
D. | 48 |
Option: C Explanation : x3 - y3 - z3 - 3xyz = (x+y+z)(x2+y2+z2-xy-yz-zx) = 9[(x + y + z)2 - 3(xy + yz + zx)] = 9(81 - 33) = 432. Click on Discuss to view users comments. |
HCF and LCM of two numbers is given. It is possible to ind out the two numbers uniquely if
I. either sum or difference between the two numbers is known.
II. HCF of two numbers = LCM of two numbers.
III. (LCM/HCF)= Prime number.
A. | I and II only |
B. | II only |
C. | II and III only |
D. | I, II and III |
Option: D Explanation :
Let HCF be h and LCM be l. Click on Discuss to view users comments. |
A number when divided by sum of 555 and 445 gives two times their diference as quotient and 30 as remainder. The number is
A. | 1220 |
B. | 1250 |
C. | 22030 |
D. | 220030 |
Option: D Explanation :
Number = (555+445)*(555-445)*2+30 Click on Discuss to view users comments. |
What is the remainder when 2050 x 2071 x 2095 is divided by 23?
A. | 17 |
B. | 12 |
C. | 6 |
D. | 3 |
Option: C Explanation :
2050 x 2071 x 2095 Click on Discuss to view users comments. Sakshi singh said: (7:38pm on Friday 21st July 2017)
but sir remainder 17 are also come .if we calculate it well, some quick arithmetic as followed by using multiples of 23 like 230,2300 etc. 2300-230=2070 is clearly a multiple of 23.(2070-2050)*(2070-2071)*(2070-2095)=20*(-1)*(-25) by 23500/23remainder is come 17.
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