Answer:
11/64
Step-by-step explanation:
Each question can be answered in 2 ways
∴ Total ways in which 10 questions can be answered
=2¹⁰
No. of ways of guessing at least 7 questions
out of 10
=7 questions correct +8 questions correct
+9 questions correct +10 questions correct
= ¹⁰C7(1)⁷+ ¹⁰C8(1)⁸+ ¹⁰C9(1)⁹+ ¹⁰C10(1)¹⁰
= 120 + 45 + 10 +1
=176
..Required Probability =176/2¹⁰
.. =11×16/2¹⁰
=11/64
Answer: x=-20
Explanation: Multiply both sides by 10
7x = -140
Divide both sides by 7
7x/7 = -140/7
x=-20
<span>Here, you can apply the Pythagorean theorem: to the right triangle formed by the ladder as the hypotenuse (side c), the wall of the building as the vertical side (side a) and the distance of the bottom of the ladder from the base of the building as the base of the right triangle, (side b).
So you are looking for the length of side a (the height the ladder reaches on the building) of the right triangle when you know the lengths of the other two sides.
Substitute c = 16 ft. (The ladder) and b = 5 ft. (The distance of the bottom of the ladder from the base of the wall)
Simplify and solve for a.
Subtract 25 from both sides.
Take the square root of both sides.
Round to the nearest tenth.
feet. 15.2 is the answer.</span>