- Option : D
- Explanation : We know that for any polynedra

F + V - E = 2; where F = number of faces

V = number of verticcs,

E = number of Edges.

∴ x + y - z = 2

⇒ x - z = 2 - y.

- Option : A
- Explanation : Given, Ravi purchase two articles for ₹1500 each.

Total CP = ₹3000.

Ravi gets 6% profit on first article, then SP of 1st article

= 1500 + 1500 x 6/100.

= ₹1590.

After selling 2nd article, he loses 4%. Then, SP of 2nd article

= 1500 - 1500 x 4/100.

= ₹1440.

∴ Total amount after selling of both article

= 1590 + 1440 = ₹3030.

∴ profit % = 30/3000 x 100% = =1 %.

*/?>

*/?>

*/?>

*/?>