9. Joanne spends of her savings on books. If she bought 4 books that costs Php 645, how much is her original savings? a. PhP 2, 580 b. PhP 6, 450 c. PhP 1, 075 d. PhP 860 10. A submarine is 75 m below sea level. It rises 29 m and then dives 19 m, ho far is the submarine below sea level? a. 65 m b. 123 m c. 27 m d. 85 11. The mass of the moon is 73,000,000,000,000,000,000,000 kg. Express th number in scientific notation a. 72 x 1021 (b, 7.3 x 1022 c. 7.3 x 10-22 d. 0.73 x 12. The rest mass of electron is 0.000 000 000 000 000 000 000 000 000 0 kg. What is this in scientific notation a. 9.1 x 10-31 b. 91 x 10-31 c. 9.1 x 1031 d. 910 13. The speed of light in vacuum is 299 792 458 m/s. Express this in scie notation. a. 2.997 924 58 x 10 c. 2.997 924 58 x 108 b. 299.792 458 x 104 d. 2.997 924 58 x 10-9 14. Write 3.56 x 1011 as an ordinary number, a. 356 000 000 000 c. 35 600 000 000 b. 356 000 000 d. 3 560 000 000 15. Write 7. 085 x 10-14 as an ordinary number. a. 0.000 000 007 085 c. 0.000 000 000 708 000 000 000 000​