61. Let
the number be X. then,
1/5 X -1/7 X =10
7X – 5X /35 = 10
2X /35 =10
X = (10 x 35/2) = 175.
62. 9
* 11 =9²
+ (11)²
-9 11 = 81 + 121 -99 =103.
63. (3*
-1) = 3 x (-1) / (3 + (-1) = -3/2. So, 3* (3* -1) =3* (-3/2) = 3 x (-3/2)/3 +
(-3/2) = -9/2 x 2/3= -3.
64. 3
* 5 + 5+ 3 = ( 2 x 3 – 3 x 5 + 3 x 5) + (2 x 5 -3 x 3 + 5 x 3)
= ( 6 + 10 – 9 + 15) = 22.
65. 4
+ (3 + p) = 4 + (3² + 2p) =4 + (9 + 2p) =4² + 2 (9 + 2p) =34 + 4p.
34 + 4p =50
4p =50 -34 =16
P=4.
66. (a
* b * c) * a * b = ( a + b /c) * a * c = ( a + /c /b = a + b + ac/b c
67. Let
the number be X. then,
