Please advise if my work is correct? I am conflicted with my answers on number 17 and 20.

For questions 17-20, use the following information. Alpha fetoprotein (AFP), a substance produced by a fetus, is often measured in pregnant women as a means of assessing whether there might be problems with fetal development. High levels of AFP have been seen in babies with neural-tube defects. A promising drug treatment is being studied to decrease AFP levels among pregnant mothers. A study consisted of 10,000 pregnant mothers were randomly assigned to either the drug treatment or a placebo group. These mothers were followed throughout the rest of their pregnancy. In the sample, 50% received the drug treatment, a total of 4% had babies born with neural-tube defects, and 60% of the pregnant mothers in the placebo group did not have a child born with a neural-tube defect. Note that you do not need to use probability for any part of this problem. Round your answers to the nearest whole number. 17. How many mothers had children born with a neural tube defect? 0.04 ( 5,000) = 200 MOTHERS, HAD CHILDREN BORN WITH ( N'T) THAT Received DRUG TREATMENT. 0.4 (5,000) - 2,00 MOTHERS, HAD CHILDREN BORN WITH (NT). Received PLACEBO. TOTAL = 21000 + 200 = 2,200 MOTHERS, HAD CHILDREN BORN WITH (ND) INT) DEFECT . ( NT ) | NO ( NT ) | TOTAL DRUG TX 200 4, 800 5, 010 PlaceBo 2000 3, 000 5, 000 TOTAL | 2 200 7,800 1 10, 000 18. How many mothers were in the placebo group? GiveN 50% OF THE 10,000 pRegNANT women WERE ON DRUG TREATMENT, Meaning THE NUMBER OF pregnant womenT ON DRUG TREATMENT is equal to 10, 00 0 ( 6. 50) = 5,000. THEREFORE, THE Remaining 10, 000- 5,000 = 5, 010 PREGNANT women were in THE PLACEBO GROUP. 19. How many mothers in the placebo group had a child born with a neural-tube defect? KNOWING THAT 60%% OF THE 5,100 PREGNANT women IN THE PLACEBO GROUP DID Not HAVE A CHILD BORN WITH ( NE). we NOW KNOW THAT THE REMAINING 40% DID HAVE A CHILD BORN WITH NF: 5, 000 (0. 40) = 2,010 pregnant women IN THE PLACEBO GROUP HAD A CHILD BORN WITH A NEURAL- TUBE Defect. 20. How many mothers in the treatment group did not have a child born with a neural-tube defect? TOTAL NUMBER OF PReck. WOMEN IN THIS STUDY THAT Received DRUG TX 5,000. We KNOW 200 MOTHERS, HAD CHILDREN BORN WITH ( NT) DEFECT THAT Received ORvg TREATMENT. THEN 5,000- 200 = 4, 800 MOTHERS IN THE TREATMENT group DID NOT Have A CHILD BORN w/ (NT) Defect. For questions 21-23, use the following information. Suppose that the annual incidence rate for 12 per 100.000 individual