7. Two bells ring at an interval of 30 minutes and 40 minutes to change the lessons in lower and upper primary respectively,
a) After how long will they ring together at the same time?
b) If they first ring together at 9:15 a. m. at what time will they ring together again?​

All cells are made of four types of acids, lipids, proteins, and carbohydrates.

When electrolyzing copper (ll) chloride, what reaction takes place at the anode? what reaction takes place at the cathode?

A100 kmol/h stream that is 97 mole% carbon tetrachloride (ccl4) and 3% carbon disulfide (cs2) is to be recovered from the bottom of a distillation column. the feed to the column is 16 mole% cs2 and 84% ccl4, and 2% of the ccl4 entering the column is contained in the overhead stream leaving the top of the column. calculate the mass and mole fractions of ccl4 in the overhead stream, and determine the molar flow rates of ccl4 and cs2 in the overhead and feed streams. 12. mw_ccla- 153.82; mw_cs2-76.14.