help me with three questions please

Question 11.11. Alexa’s gross monthly pay is $3810.

To maintain her current way of life, how much should she have saved by the time she retires?
(Points : 5)
$457,200
$464,400
$487,200
$493,600

Question 12.12. Radon-219 has a half-life of about 4 s.

After 20 s, how many milligrams of a 500 mg sample will remain?
(Points : 5)
435.3 mg
211.6 mg
31.3 mg
15.6 mg

Question

help me with three questions please 

Question 11.11. Alexa’s gross monthly pay is $3810. 

To maintain her current way of life, how much should she have saved by the time she retires? 
(Points : 5)
       $457,200
       $464,400
       $487,200
       $493,600


Question 12.12. Radon-219 has a half-life of about 4 s. 

After 20 s, how many milligrams of a 500 mg sample will remain? 
(Points : 5)
       435.3 mg
       211.6 mg
       31.3 mg
       15.6 mg

anonymous · Answer

13. A ladder that is 32 ft long leans against a building. The angle of elevation of the ladder is 70°. 

To the nearest tenth of a foot, how high off the ground is the top of the ladder? 
(Points : 5)
       20.3 ft
       24.8 ft
       26.2 ft
       39.1 ft

triciaal · Answer

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